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[READ-ONLY] Mirror of https://github.com/emilyhunt/thesis. My PhD thesis.
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title = {Catalogue Des N\'ebuleuses et Des Amas d'{{\'Etoiles}} (Catalog of Nebulae and Star Clusters)}, author = {Messier, Charles}, year = {1781}, month = jan, pages = {227--267}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1781cote.rept..227M}, howpublished = {Connoissance des Temps ou des Mouvements C\'elestes, for 1784, p. 227-267}}
@inproceedings{2015ASSL..413...29M, title = {The Blue Stragglers of the Old Open Cluster {{NGC}} 188}, booktitle = {Astrophysics and Space Science Library}, author = {Mathieu, Robert D. and Geller, Aaron M.}, editor = {Boffin, Henri M. J. and Carraro, Giovanni and Beccari, Giacomo}, year = {2015}, month = jan, series = {Astrophysics and Space Science Library}, volume = {413}, eprint = {1406.3467}, primaryclass = {astro-ph.SR}, pages = {29}, doi = {10.1007/978-3-662-44434-4_3}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2015ASSL..413...29M}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics,Physics}}
@article{2015MNRAS.450.3750M, title = {Multiple Stellar Populations in {{Magellanic Cloud}} Clusters - {{III}}. {{The}} First Evidence of an Extended Main Sequence Turn-off in a Young Cluster: {{NGC}} 1856}, author = {Milone, A. P. and Bedin, L. R. and Piotto, G. and Marino, A. F. and Cassisi, S. and Bellini, A. and Jerjen, H. and Pietrinferni, A. and Aparicio, A. and Rich, R. M.}, year = {2015}, month = jul, volume = {450}, number = {4}, eprint = {1504.03252}, primaryclass = {astro-ph.SR}, pages = {3750--3764}, doi = {10.1093/mnras/stv829}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2015MNRAS.450.3750M}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics,globular clusters: general,globular clusters: individual: NGC1856,Magellanic Clouds,stars: Population II,stars: rotation}}
@misc{abadi_tensorflow_2015, title = {{{TensorFlow}}: {{Large-Scale Machine Learning}} on {{Heterogeneous Systems}}}, author = {Abadi, Mart{\'i}n and Agarwal, Ashish and Barham, Paul and Brevdo, Eugene and Chen, Zhifeng and {Craig Citro} and {Greg S. Corrado} and {Andy Davis} and {Jeffrey Dean} and {Matthieu Devin} and {Sanjay Ghemawat} and {Ian Goodfellow} and {Andrew Harp} and {Geoffrey Irving} and {Michael Isard} and Jia, Yangqing and {Rafal Jozefowicz} and {Lukasz Kaiser} and {Manjunath Kudlur} and {Josh Levenberg} and {Dandelion Man\'e} and {Rajat Monga} and {Sherry Moore} and {Derek Murray} and {Chris Olah} and {Mike Schuster} and {Jonathon Shlens} and {Benoit Steiner} and {Ilya Sutskever} and {Kunal Talwar} and {Paul Tucker} and {Vincent Vanhoucke} and {Vijay Vasudevan} and {Fernanda Vi\'egas} and {Oriol Vinyals} and {Pete Warden} and {Martin Wattenberg} and {Martin Wicke} and {Yuan Yu} and {Xiaoqiang Zheng}}, year = {2015}}
@article{abadi_tensorflow_2016, title = {{{TensorFlow}}: {{A}} System for Large-Scale Machine Learning}, author = {Abadi, Mart{\i}n and Barham, Paul and Chen, Jianmin and Chen, Zhifeng and Davis, Andy and Dean, Jeffrey and Devin, Matthieu and Ghemawat, Sanjay and Irving, Geoffrey and Isard, Michael and Kudlur, Manjunath and Levenberg, Josh and Monga, Rajat and Moore, Sherry and Murray, Derek G and Steiner, Benoit and Tucker, Paul and Vasudevan, Vijay and Warden, Pete and Wicke, Martin and Yu, Yuan and Zheng, Xiaoqiang}, year = {2016}, journal = {Proceedings of the 12th USENIX Symposium on Operating Systems Design and Implementation}, pages = {21}, abstract = {TensorFlow is a machine learning system that operates at large scale and in heterogeneous environments. TensorFlow uses dataflow graphs to represent computation, shared state, and the operations that mutate that state. It maps the nodes of a dataflow graph across many machines in a cluster, and within a machine across multiple computational devices, including multicore CPUs, generalpurpose GPUs, and custom-designed ASICs known as Tensor Processing Units (TPUs). This architecture gives flexibility to the application developer: whereas in previous ``parameter server'' designs the management of shared state is built into the system, TensorFlow enables developers to experiment with novel optimizations and training algorithms. TensorFlow supports a variety of applications, with a focus on training and inference on deep neural networks. Several Google services use TensorFlow in production, we have released it as an open-source project, and it has become widely used for machine learning research. In this paper, we describe the TensorFlow dataflow model and demonstrate the compelling performance that TensorFlow achieves for several real-world applications.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\XS7UDH6M\\Abadi et al. - TensorFlow A system for large-scale machine learn.pdf}}
@article{adamo_star_2020, title = {Star Clusters near and Far; Tracing Star Formation across Cosmic Time}, author = {Adamo, Angela and Zeidler, Peter and Kruijssen, J. M. Diederik and Chevance, M{\'e}lanie and Gieles, Mark and Calzetti, Daniela and Charbonnel, Corinne and Zinnecker, Hans and Krause, Martin G. H.}, year = {2020}, month = may, journal = {arXiv:2005.06188 [astro-ph]}, eprint = {2005.06188}, primaryclass = {astro-ph}, urldate = {2020-05-15}, abstract = {Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\textbackslash{} detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\P8EIDSK4\\2005.html}}
@article{agarwal_ml-moc_2020, title = {{{ML-MOC}}: {{Machine Learning}} Based {{Membership Determination}} for {{Open Clusters}}}, shorttitle = {{{ML-MOC}}}, author = {Agarwal, Manan and Rao, Khushboo K. and Vaidya, Kaushar and Bhattacharya, Souradeep}, year = {2020}, month = nov, journal = {arXiv:2011.13622 [astro-ph]}, eprint = {2011.13622}, primaryclass = {astro-ph}, urldate = {2021-01-05}, abstract = {The existing open cluster membership determination algorithms are either prior dependent on some known parameters of clusters or are not automatable to large samples of clusters. In this paper, we present, ML-MOC, a new machine learning based approach to identify likely members of open clusters using the Gaia DR2 data, and no a priori information about the clusters. We use the k-Nearest Neighbours algorithm and the Gaussian Mixture Model on the high-precision proper motions and parallax measurements from Gaia DR2 data to determine the membership probabilities of individual sources down to G \textasciitilde 20 mag. To validate the developed method, we apply it on thirteen open clusters: M67, NGC 2099, NGC 2141, NGC 2243, NGC 2539, NGC 6253, NGC 6405, NGC 6791, NGC 7044, NGC 7142, NGC 752, Berkeley 18, and IC 4651. These clusters differ in terms of their ages, distances, metallicities, extinctions and cover a wide parameter space in proper motions and parallaxes with respect to the field population. The extracted members produce clean colour-magnitude diagrams and our astrometric parameters of the clusters are in good agreement with the values derived by the previous works. The degree of contamination in the extracted members range between 2\% and 12\%. The results show that ML-MOC is a reliable and scalable approach to segregate the open cluster members from the field stars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SI3SIPYC\\2011.html}}
@article{aghakhanloo_inferring_2020, title = {Inferring the Parallax of {{Westerlund}} 1 from {{Gaia DR2}}}, author = {Aghakhanloo, Mojgan and Murphy, Jeremiah W. and Smith, Nathan and Parejko, John and {D{\'i}az-Rodr{\'i}guez}, Mariangelly and Drout, Maria R. and Groh, Jose H. and Guzman, Joseph and Stassun, Keivan G.}, year = {2020}, month = jan, journal = {arXiv:1901.06582 [astro-ph]}, eprint = {1901.06582}, primaryclass = {astro-ph}, doi = {10.1093/mnras/stz3628/5691334}, urldate = {2020-01-20}, abstract = {Westerlund 1 (Wd1) is potentially the largest star cluster in the Galaxy. That designation critically depends upon the distance to the cluster, yet the cluster is highly obscured, making luminosity-based distance estimates difficult. Using \{\textbackslash it Gaia\} Data Release 2 (DR2) parallaxes and Bayesian inference, we infer a parallax of \$0.35\^\{+0.07\}\_\{-0.06\}\$ mas corresponding to a distance of \$2.6\^\{+0.6\}\_\{-0.4\}\$ kpc. To leverage the combined statistics of all stars in the direction of Wd1, we derive the Bayesian model for a cluster of stars hidden among Galactic field stars; this model includes the parallax zero point. Previous estimates for the distance to Wd1 ranged from 1.0 to 5.5 kpc, although values around 5 kpc have usually been adopted. The \{\textbackslash it Gaia\} DR2 parallaxes reduce the uncertainty from a factor of 3 to 18\textbackslash\% and rules out the most often quoted value of 5 kpc with 99\textbackslash\% confidence. This new distance allows for more accurate mass and age determinations for the stars in Wd1. For example, the previously inferred initial mass at the main-sequence turn-off was around 40 M\$\_\{\textbackslash odot\}\$; the new \{\textbackslash it Gaia\} DR2 distance shifts this down to about 22 M\$\_\{\textbackslash odot\}\$. This has important implications for our understanding of the late stages of stellar evolution, including the initial mass of the magnetar and the LBV in Wd1. Similarly, the new distance suggests that the total cluster mass is about four times lower than previously calculated.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\KCVD8AH7\\1901.html}}
@article{albarran_gaia-eso_2020, title = {The {{Gaia-ESO Survey}}: {{Calibrating}} the Lithium-Age Relation with Open Clusters and Associations. {{I}}. {{Cluster}} Age Range and Initial Membership Selections}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Albarr{\'a}n, M. L. Guti{\'e}rrez and Montes, D. and Garrido, M. G{\'o}mez and Tabernero, H. M. and Hern{\'a}ndez, J. I. G{\'o}nzalez and Marfil, E. and Frasca, A. and Lanzafame, A. C. and Klutsch, A. and Franciosini, E. and Randich, S. and Smiljanic, R. and Korn, A. J. and Gilmore, G. and Alfaro, E. J. and Baratella, M. and Bayo, A. and Bensby, T. and Bonito, R. and Carraro, G. and Mena, E. Delgado and Feltzing, S. and Gonneau, A. and Heiter, U. and Hourihane, A. and Esteban, F. Jim{\'e}nez and Jofre, P. and Masseron, T. and Monaco, L. and Morbidelli, L. and Prisinzano, L. and Roccatagliata, V. and Sousa, S. and {Van der Swaelmen}, M. and Worley, C. C. and Zaggia, S.}, year = {2020}, month = aug, journal = {Astronomy \& Astrophysics}, eprint = {2009.00610}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202037620}, urldate = {2020-09-04}, abstract = {Previous studies of open clusters have shown that lithium depletion is not only strongly age dependent but also shows a complex pattern with other parameters that is not yet understood. For pre- and main-sequence late-type stars, these parameters include metallicity, mixing mechanisms, convection structure, rotation, and magnetic activity. We perform a thorough membership analysis for a large number of stars observed within the Gaia-ESO survey (GES) in the field of 20 open clusters, ranging in age from young clusters and associations, to intermediate-age and old open clusters. Based on the parameters derived from the GES spectroscopic observations, we obtained lists of candidate members for each of the clusters in the sample by deriving RV distributions and studying the position of the kinematic selections in the EW(Li) versus Teff plane to obtain lithium members. We used gravity indicators to discard field contaminants and studied [Fe/H] metallicity to further confirm the membership of the candidates. We also made use of studies using recent data from the Gaia DR1 and DR2 releases to assess our member selections. We identified likely member candidates for the sample of 20 clusters observed in GES (iDR4) with UVES and GIRAFFE, and conducted a comparative study that allowed us to characterize the properties of these members, as well as identify field contaminant stars, both lithium-rich giants and non-giant outliers. This work is the first step towards the calibration of the lithium-age relation and its dependence on other GES parameters. During this project we aim to use this relation to infer the ages of GES field stars, and identify their potential membership to young associations and stellar kinematic groups of different ages.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HLT4JHVT\\2009.html}}
@book{alter_catalogue_star_1970, title = {Catalogue of Star Clusters and Associations}, author = {Alter, Georg and Balazs, Bela and Ruprecht, J. and Vanysek, J.}, year = {1970}, month = jan, journal = {Budapest: Akademiai Kiado}, urldate = {2023-04-06}, keywords = {CATALOGS,STAR ASSOCIATIONS,STAR CLUSTERS,STARS: CLUSTERS: CATALOGS,STELLAR ASSOCIATIONS: CATALOGS}, annotation = {ADS Bibcode: 1970csca.book.....A}}
@article{an_blueprint_2019, title = {A {{Blueprint}} for the {{Milky Way}}'s {{Stellar Populations}}: {{The Power}} of {{Large Photometric}} and {{Astrometric Surveys}}}, shorttitle = {A {{Blueprint}} for the {{Milky Way}}'s {{Stellar Populations}}}, author = {An, Deokkeun and Beers, Timothy C.}, year = {2019}, month = dec, journal = {arXiv:1912.06847 [astro-ph]}, eprint = {1912.06847}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {Recent advances from astronomical surveys have revealed spatial, chemical, and kinematical inhomogeneities in the inner region of the stellar halo of the Milky Way Galaxy. In particular, large spectroscopic surveys, combined with Gaia astrometric data, have provided powerful tools for analyzing the detailed abundances and accurate kinematics for individual stars. Despite these noteworthy efforts, however, spectroscopic samples are typically limited by the numbers of stars considered; their analysis and interpretation are also hampered by the complex selection functions that are often employed. Consequently, piecewise information on individual components must be stitched together in order to reconstruct the multi-dimensional structure of the Milky Way's stellar populations. Here we present a powerful alternative approach - a synoptic view of the spatial, chemical, and kinematical distributions of stars in the Milky Way based on large photometric survey databases, enabled by a well-calibrated technique for obtaining individual stellar metal abundances from broad-band photometry. We combine metallicities with accurate proper motions from the Gaia mission along the Prime Meridian of the Galaxy, and find that various stellar components are clearly separated from each other in the metallicity versus rotation-velocity space. The observed metallicity distribution of the inner-halo stars deviates from the traditional single-peaked distribution, and exhibits complex substructures comprising varying contributions from individual stellar populations, sometimes with striking double peaks at low metallicities. The substructures revealed from our maps demonstrate the clear advantages of this approach, which can be built upon by future mixed-band and broad-band photometric surveys, and used as a blueprint for identifying the stars of greatest interest for upcoming spectroscopic studies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{anders_milky_2020, title = {The {{Milky Way}}'s Cluster Age Function in Light of {{Gaia DR2}}}, author = {Anders, Friedrich and {Cantat-Gaudin}, Tristan and {Quadrino-Lodoso}, Irene and Jordi, Carme and Gieles, Mark and {Castro-Ginard}, Alfred and {Balaguer-N{\'u}{\~n}ez}, Lola}, year = {2020}, month = jun, journal = {arXiv:2006.01690 [astro-ph]}, eprint = {2006.01690}, primaryclass = {astro-ph}, urldate = {2020-06-03}, abstract = {We perform a systematic reanalysis of the age distribution of Galactic open star clusters. Using a catalogue of homogeneously determined ages for 834 open clusters contained in a 2 kpc cylinder around the Sun and characterised with astrometric and photometric data from the Gaia satellite, we find that it is necessary to revise earlier works that relied on data from the Milky Way Star Cluster survey. After establishing age-dependent completeness limits for our sample, we find that the cluster age function in the range \$6.5 {$<$} \textbackslash log t{$<$}10\$ is compatible with a Schechter-type or broken power-law function, whose parameters we determine by MCMC fitting. Our best-fit values indicate an earlier drop of the age function (by a factor of \$2-3\$) with respect to the results obtained in the last five years, and are instead more compatible with results obtained in the early 2000s and radio observations of inner-disc clusters. Furthermore, we find excellent agreement with the dynamical cluster formation and destruction models of Lamers et al. (2005), indicating a typical destruction time-scale of \$\textbackslash sim1.5\$ Gyr for a \$10\^4\textbackslash, \{\textbackslash rm M\}\_\{\textbackslash odot\}\$ cluster and a present-day cluster-formation rate of \$\textbackslash sim 0.6\textbackslash pm 0.1\$ Myr\$\^\{-1\}\$kpc\$\^\{-2\}\$, suggesting that only \$8-15\textbackslash, \textbackslash\%\$ of all stars born in the solar neighbourhood form in bound clusters. Accurate cluster-mass measurements are now needed to place more precise constraints on open-cluster formation and evolution models.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\I2Z4CL8W\\2006.html}}
@article{anders_ngc_2022-1, title = {{{NGC}} 1605 Is Not a {{Binary Cluster}}}, author = {Anders, Friedrich and {Castro-Ginard}, Alfred and Casado, Juan and Jordi, Carme and {Balaguer-N{\'u}{\~n}ez}, Lola}, year = {2022}, month = mar, journal = {Research Notes of the American Astronomical Society}, volume = {6}, pages = {58}, issn = {2515-5172}, doi = {10.3847/2515-5172/ac6034}, urldate = {2023-02-28}, abstract = {The open star cluster NGC 1605 has recently been reported to in fact consist of two clusters (one intermediate-aged and one old) that merged via a flyby capture. Here we show that Gaia data do not support this scenario. We also report the serendipitous discovery of a new open cluster, Can Batll\'o 1, with a similar age and distance.}, keywords = {1052,1160,1882,1908,80,Astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Astrostatistics,Clustering,Milky Way evolution,Open star clusters}}
@article{anders_photo-astrometric_2019, title = {Photo-Astrometric Distances, Extinctions, and Astrophysical Parameters for {{Gaia DR2}} Stars Brighter than {{G}} = 18}, author = {Anders, F. and Khalatyan, A. and Chiappini, C. and Queiroz, A. B. and Santiago, B. X. and Jordi, C. and Girardi, L. and Brown, A. G. A. and Matijevi{\v c}, G. and Monari, G. and {Cantat-Gaudin}, T. and Weiler, M. and Khan, S. and Miglio, A. and Carrillo, I. and {Romero-G{\'o}mez}, M. and Minchev, I. and de Jong, R. S. and Antoja, T. and Ramos, P. and Steinmetz, M. and Enke, H.}, year = {2019}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {628}, pages = {A94}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201935765}, urldate = {2020-02-07}, abstract = {Combining the precise parallaxes and optical photometry delivered by \emph{Gaia{$<$}i/{$>$}'s second data release with the photometric catalogues of Pan-STARRS1, 2MASS, and AllWISE, we derived Bayesian stellar parameters, distances, and extinctions for 265 million of the 285 million objects brighter than \emph{G{$<$}i/{$>$} = 18. Because of the wide wavelength range used, our results substantially improve the accuracy and precision of previous extinction and effective temperature estimates. After cleaning our results for both unreliable input and output data, we retain 137 million stars, for which we achieve a median precision of 5\% in distance, 0.20 mag in \emph{V{$<$}i/{$>$}-band extinction, and 245 K in effective temperature for \emph{G{$<$}i/{$>$} {$\leq$} 14, degrading towards fainter magnitudes (12\%, 0.20 mag, and 245 K at \emph{G{$<$}i/{$>$} = 16; 16\%, 0.23 mag, and 260 K at \emph{G{$<$}i/{$>$} = 17, respectively). We find a very good agreement with the asteroseismic surface gravities and distances of 7000 stars in the \emph{Kepler{$<$}i/{$>$}, K2-C3, and K2-C6 fields, with stellar parameters from the APOGEE survey, and with distances to star clusters. Our results are available through the ADQL query interface of the \emph{Gaia{$<$}i/{$>$} mirror at the Leibniz-Institut f\"ur Astrophysik Potsdam (gaia.aip.de) and as binary tables at data.aip.de. As a first application, we provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps as a function of distance, and extensive density maps. These demonstrate the potential of our value-added dataset for mapping the three-dimensional structure of our Galaxy. In particular, we see a clear manifestation of the Galactic bar in the stellar density distributions, an observation that can almost be considered direct imaging of the Galactic bar.}}}}}}}}}, copyright = {\textcopyright{} ESO 2019}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QQHCJD5S\\aa35765-19.html}}
@article{anders_photo-astrometric_2021, title = {Photo-Astrometric Distances, Extinctions, and Astrophysical Parameters for {{Gaia EDR3}} Stars Brighter than {{G}}=18.5}, author = {Anders, F. and Khalatyan, A. and Queiroz, A. B. A. and Chiappini, C. and Ard{\`e}vol, J. and Casamiquela, L. and Figueras, F. and {Jim{\'e}nez-Arranz}, {\'O} and Jordi, C. and Mongui{\'o}, M. and {Romero-G{\'o}mez}, M. and Altamirano, D. and Antoja, T. and Assaad, R. and {Cantat-Gaudin}, T. and {Castro-Ginard}, A. and Enke, H. and Girardi, L. and Guiglion, G. and Khan, S. and Luri, X. and Miglio, A. and Minchev, I. and Ramos, P. and Santiago, B. X. and Steinmetz, M.}, year = {2021}, month = nov, journal = {arXiv:2111.01860 [astro-ph]}, eprint = {2111.01860}, primaryclass = {astro-ph}, urldate = {2021-11-04}, abstract = {We present a catalogue of 362 million stellar parameters, distances, and extinctions derived from Gaia's early third data release (EDR3) cross-matched with the photometric catalogues of Pan-STARRS1, SkyMapper, 2MASS, and AllWISE. The higher precision of the Gaia EDR3 data, combined with the broad wavelength coverage of the additional photometric surveys and the new stellar-density priors of the \{\textbackslash tt StarHorse\} code allow us to substantially improve the accuracy and precision over previous photo-astrometric stellar-parameter estimates. At magnitude \$G=14\textbackslash, (17)\$, our typical precisions amount to 3\% (15\%) in distance, 0.13 mag (0.15 mag) in \$V\$-band extinction, and 140 K (180 K) in effective temperature. Our results are validated by comparisons with open clusters, as well as with asteroseismic and spectroscopic measurements, indicating systematic errors smaller than the nominal uncertainties for the vast majority of objects. We also provide distance- and extinction-corrected colour-magnitude diagrams, extinction maps, and extensive stellar density maps that reveal detailed substructures in the Milky Way and beyond. The new density maps now probe a much greater volume, extending to regions beyond the Galactic bar and to Local Group galaxies, with a larger total number density. We publish our results through an ADQL query interface (\{\textbackslash tt gaia.aip.de\}) as well as via tables containing approximations of the full posterior distributions. Our multi-wavelength approach and the deep magnitude limit make our results useful also beyond the next Gaia release, DR3.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2B5V98LH\\2111.html}}
@article{angelo_catching_2018, title = {Catching {{Galactic}} Open Clusters in Advanced Stages of Dynamical Evolution}, author = {Angelo, M. S. and Piatti, A. E. and Dias, W. S. and Maia, F. F. S.}, year = {2018}, month = jul, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {477}, number = {3}, pages = {3600--3622}, issn = {0035-8711}, doi = {10.1093/mnras/sty875}, urldate = {2019-11-21}, abstract = {Abstract. During their dynamical evolution, Galactic open clusters (OCs) gradually lose their stellar content mainly because of internal relaxation and tidal f}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2UQ6S22C\\4963760.html}}
@article{angelo_characterizing_2020, title = {Characterizing Low Contrast {{Galactic}} Open Clusters with {{GAIA DR2}}}, author = {Angelo, M. S. and Santos Jr, J. F. C. and Corradi, W. J. B.}, year = {2020}, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2002.06158}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa517}, urldate = {2020-02-21}, abstract = {In this study, we characterized 16 objects previously classified as faint or low contrast Galactic open clusters (OCs). We employed parameters associated to the OCs dynamical evolution: core (\$r\_c\$), tidal (\$r\_t\$) and half-mass (\$r\_\{hm\}\$) radii, age and crossing time (\$t\_\{cr\}\$). Relations among these parameters were exploited to draw some evolutionary connections. We also included 11 OCs with previous characterizations to provide wider coverage of the parameters space. The investigated sample spans a considerable range in age (log (t/yr) \textasciitilde 7.0 - 9.7) and Galactocentric distance (\$R\_G\$ \textasciitilde{} 6 - 11 kpc). Most of them present solar metallicity. We employed GAIA DR2 astrometry and photometry and selected member stars through a decontamination algorithm which explores the 3D astrometric space (\$\textbackslash mu\_\{\textbackslash alpha\}\$, \$\textbackslash mu\_\{\textbackslash delta\}\$, \$\textbackslash varpi\$) to assign membership likelihoods. Previous studies of most of these objects were based mostly on photometric information. All investigated OCs were proved to be real stellar concentrations and relations among their parameters indicate a general disruption scenario in which OCs tend to be more concentrated as they evolve. Internal interactions sucessively drive OCs to develop more dynamically relaxed structures and make them less subject to mass loss due to tidal effects. Tidal radius tends to increase with \$R\_G\$ in accordance with the strength of the Galactic tidal field. Besides, the correlation between the \$r\_c\$ and the dynamical ratio \$\textbackslash tau\_\{\textbackslash textrm\{dyn\}\}\$ = age/\$t\_\{cr\}\$ suggests two distinct evolutionary sequences, which may be consequence of different initial formation conditions.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CB68KQGG\\2002.html}}
@article{angelo_characterizing_2020-1, title = {Characterizing Dynamical States of {{Galactic}} Open Clusters with {{Gaia DR2}}}, author = {Angelo, M. S. and Corradi, W. J. B. and Santos Jr., J. F. C. and Maia, F. F. S. and Ferreira, F. A.}, year = {2020}, month = oct, journal = {arXiv:2010.04825 [astro-ph]}, eprint = {2010.04825}, primaryclass = {astro-ph}, urldate = {2020-10-13}, abstract = {In this work, we investigate the dynamical properties of 38 Galactic open clusters: 34 of them are located at low Galactic latitudes (|b| {$<$} 10\$\^\{\textbackslash circ\}\$) and are projected against dense stellar fields; the other 4 comparison objects present clearer contrasts with the field population. We determine structural and time-related parameters that are associated with the clusters' dynamical evolution: core (\$r\_c\$), tidal (\$r\_t\$) and half-mass (\$r\_\{hm\}\$) radii, ages (\$t\$) and crossing times (\$t\_\{cr\}\$). We have also incorporated results for 27 previously studied clusters, creating a sample of 65, spanning the age and Galactocentric distance (\$R\_G\$) ranges: 7.0 {$<$} log (\$t\$) {$<$} 9.7 and 6 {$<$} \$R\_G\$ (kpc) {$<$} 13. We employ a uniform analysis method which incorporates photometric and astrometric data from the Gaia DR2 catalogue. Member stars are identified by employing a decontamination algorithm which operates on the 3D astrometric space of parallax and proper motion and attributes membership likelihoods for stars in the cluster region. Our results show that the internal relaxation causes \$r\_c\$ to correlate negatively with the dynamical ratio \$\textbackslash tau\_\{dyn\}\$ = \$t/t\_\{cr\}\$. This implies that dynamically older systems tend to be more centrally concentrated. The more concentrated ones tend to present smaller \$r\_\{hm\}/r\_t\$ ratios, which means that they are less subject to tidal disruption. The analysis of coeval groups at compatible \$R\_G\$ suggests that the inner structure of clusters is reasonably insensitive to variations in the external tidal field. Additionally, our results confirm, on average, an increase in \$r\_t\$ for regions with less intense Galactic gravitational field.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5Q6G73TG\\2010.html}}
@misc{angelo_enlightening_dynamical_2023, title = {Enlightening the Dynamical Evolution of {{Galactic}} Open Clusters: An Approach Using {{Gaia DR3}} and Analytical Descriptions}, shorttitle = {Enlightening the Dynamical Evolution of {{Galactic}} Open Clusters}, author = {Angelo, M. S. and Santos Jr., J. F. C. and Maia, F. F. S. and Corradi, W. J. B.}, year = {2023}, month = apr, number = {arXiv:2304.02209}, eprint = {2304.02209}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2304.02209}, urldate = {2023-04-06}, abstract = {Most stars in our Galaxy form in stellar aggregates, which can become long-lived structures called open clusters (OCs). Along their dynamical evolution, their gradual depletion leave some imprints on their structure. In this work, we employed astrometric, photometric and spectroscopic data from the \textbackslash textit\{Gaia\} DR3 catalogue to uniformly characterize a sample of 60 OCs. Structural parameters (tidal, core and half-light radii, respectively, \$r\_t\$, \$r\_c\$ and \$r\_h\$), age, mass (\$M\_\{\textbackslash textrm\{clu\}\}\$), distance, reddening, besides Jacobi radius (\$R\_J\$) and half-light relaxation time (\$t\_\{rh\}\$), are derived from radial density profiles and astrometrically decontaminated colour-magnitude diagrams. Ages and Galactocentric distances (\$R\_G\$) range from 7.2\$\textbackslash,\textbackslash lesssim\textbackslash,\$log(\$t.\$yr\$\^\{-1\}\$)\$\textbackslash,\textbackslash lesssim\textbackslash,\$9.8 and 6\$\textbackslash,\textbackslash lesssim\textbackslash,R\_G\$(kpc)\$\textbackslash,\textbackslash lesssim\textbackslash,\$12. Analytical expressions derived from \$N\$-body simulations, taken from the literature, are also employed to estimate the OC initial mass (\$M\_\{\textbackslash textrm\{ini\}\}\$) and mass loss due to exclusively dynamical effects. Both \$r\_c\$ and the tidal filling ratio, \$r\_h/R\_J\$, tend to decrease with the dynamical age (=\$t/t\_\{rh\}\$), indicating the shrinking of the OCs' internal structure as consequence of internal dynamical relaxation. This dependence seems differentially affected by the external tidal field, since OCs at smaller \$R\_G\$ tend to be dynamically older and have smaller \$M\_\{\textbackslash textrm\{clu\}\}/M\_\{\textbackslash textrm\{ini\}\}\$ ratios. In this sense, for \$R\_G\textbackslash lesssim8\textbackslash,\$kpc, the \$r\_h/R\_J\$ ratio presents a slight positive correlation with \$R\_G\$. Beyond this limit, there is a dichotomy in which more massive OCs tend to be more compact and therefore less subject to tidal stripping in comparison to those less massive and looser OCs at similar \$R\_G\$. Besides, the \$r\_t/R\_J\$ ratio also tends to correlate positively with \$R\_G\$.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{angelo_investigating_2021, title = {Investigating {{Galactic}} Binary Cluster Candidates with {{Gaia EDR3}}}, author = {Angelo, M. S. and Santos Jr, J. F. C. and Maia, F. F. S. and Corradi, W. J. B.}, year = {2021}, month = dec, journal = {arXiv:2112.15247 [astro-ph]}, eprint = {2112.15247}, primaryclass = {astro-ph}, urldate = {2022-01-11}, abstract = {A number of stellar open cluster (OC) pairs in the Milky Way occupy similar positions in the phase space (coordinates, parallax and proper motions) and therefore may constitute physically interacting systems. The characterization of such objects based on observational data is a fundamental step towards a proper understanding of their physical status and to investigate cluster pair formation in the Galaxy. In this work, we employed Gaia EDR3 data to investigate a set of 16 OCs distributed as seven stellar aggregates. We determined structural parameters and applied a decontamination technique that allowed to obtain unambiguous lists of member stars. The studied OCs span Galactocentric distances and ages in the ranges \textasciitilde 7 {$<$} \$R\_G\$ (kpc) {$<$} \textasciitilde 11 and 7.3 {$<$}= log t {$<$}= 9.2. Eight OCs were found to constitute 4 gravitationally bound pairs (NGC5617-Trumpler22, Collinder394-NGC6716, Ruprecht100-Ruprecht101, NGC659-NGC663, the latter being a dynamically unevolved binary) and other 4 clusters constitute 2 interacting, but gravitationally unbound, pairs (King16-Berkeley4, NGC2383-NGC2384, the latter being a dissolving OC). Other 4 OCs (Dias1, Pismis19, Czernik20, NGC1857) seem not associated to any stellar aggregates. Apparently, clusters within bound and dynamically evolved pairs tend to present ratios of half-light to tidal radius larger than single clusters located at similar \$R\_G\$, suggesting that mutual tidal interactions may possibly affect their structural parameters. Unbound or dynamically unevolved systems seems to present less noticeable signature of tidal forces on their structure. Moreover, the core radius seems more importantly correlated with the clusters' internal dynamical relaxation process.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\S6DQSYAC\\2112.html}}
@inproceedings{ankerst_optics_1999, title = {{{OPTICS}}: {{Ordering Points To Identify}} the {{Clustering Structure}}}, booktitle = {Proc. {{ACM SIGMOD}}'99 {{Int}}. {{Conf}}. on {{Management}} of {{Data}}}, author = {Ankerst, Mihael and Breunig, Markus M and Kriegel, Hans-Peter and Sander, J{\"o}rg}, year = {1999}, pages = {12}, address = {{Philadelphia PA}}, abstract = {Cluster analysis is a primary method for database mining. It is either used as a stand-alone tool to get insight into the distribution of a data set, e.g. to focus further analysis and data processing, or as a preprocessing step for other algorithms operating on the detected clusters. Almost all of the well-known clustering algorithms require input parameters which are hard to determine but have a significant influence on the clustering result. Furthermore, for many real-data sets there does not even exist a global parameter setting for which the result of the clustering algorithm describes the intrinsic clustering structure accurately. We introduce a new algorithm for the purpose of cluster analysis which does not produce a clustering of a data set explicitly; but instead creates an augmented ordering of the database representing its density-based clustering structure. This cluster-ordering contains information which is equivalent to the density-based clusterings corresponding to a broad range of parameter settings. It is a versatile basis for both automatic and interactive cluster analysis. We show how to automatically and efficiently extract not only `traditional' clustering information (e.g. representative points, arbitrary shaped clusters), but also the intrinsic clustering structure. For medium sized data sets, the cluster-ordering can be represented graphically and for very large data sets, we introduce an appropriate visualization technique. Both are suitable for interactive exploration of the intrinsic clustering structure offering additional insights into the distribution and correlation of the data.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M827XENL\\Ankerst et al. - OPTICS Ordering Points To Identify the Clustering.pdf}}
@article{apellaniz_villafranca_2020, title = {The {{Villafranca}} Catalog of {{Galactic OB}} Groups: {{I}}. {{Systems}} with {{O2-O3}}.5 Stars}, shorttitle = {The {{Villafranca}} Catalog of {{Galactic OB}} Groups}, author = {Apell{\'a}niz, J. Ma{\'i}z and Bellido, P. Crespo and Barb{\'a}, R. H. and Aranda, R. Fern{\'a}ndez and Sota, A.}, year = {2020}, month = sep, journal = {arXiv:2009.05773 [astro-ph]}, eprint = {2009.05773}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {CONTEXT. The GOSSS spectral classifications and Gaia data have significantly improved our ability to measure distances and determine memberships of stellar groups with OB stars. AIMS. We have started a program to identify, measure distances, and determine the membership of Galactic stellar groups with OB stars. We start with the identification and distance determinations of groups with O stars. In this paper we concentrate on groups that contain stars with the earliest spectral subtypes. METHODS. We use GOSSS to select Galactic stellar groups with O2-O3.5 stars and a method that combines Gaia DR2 photometry, positions, proper motions, and parallaxes to assign robust memberships and measure distances. We also include the two clusters in that paper to generate our first list of 16 O-type Galactic stellar groups. RESULTS. We derive distances, determine the membership, and analyze the structure of sixteen Galactic stellar groups with O stars, Villafranca O-001 to O-016, including the 14 groups with the earliest-O-type optically-accessible stars known in the Milky Way. We compare our distance with previous results and establish that the best consistency is with VLBI parallaxes and the worst is with kinematic distances. Our results indicate that massive stars can form in relatively low-mass clusters or even in near-isolation, as is the case for the Bajamar star in the North America nebula. This lends support to the hierarchical scenario of star formation, where some stars are born in well-defined bound clusters but others are born in associations that are unbound from the beginning: groups of newborn stars come in many shapes and sizes. We propose that HD 64 568 and HD 64 315 AB could have been ejected simultaneously from Villafranca O-012 S. Our results are consistent with a difference of approx. 20 microas in the Gaia DR2 parallax zero point between bright and faint stars. (ABRIDGED)}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\X7QNUSYA\\2009.html}}
@article{asad_precision_2020, title = {On the {{Precision}} of {{Full-spectrum Fitting}} of {{Simple Stellar Populations}}. {{I}}. {{Well-sampled Populations}}}, author = {Asa'd, Randa and Goudfrooij, Paul}, year = {2020}, month = aug, journal = {arXiv:2008.07582 [astro-ph]}, eprint = {2008.07582}, primaryclass = {astro-ph}, urldate = {2020-08-21}, abstract = {We investigate the precision of the ages and metallicities of 21,000 mock simple stellar populations (SSPs) determined through full-spectrum fitting. The mock SSPs cover an age range of 6.8 \${$<\$$} log (age/yr) \${$<\$$} 10.2, for three wavelength ranges in the optical regime, using both Padova and MIST isochrone models. Random noise is added to the model spectra to achieve S/N ratios between 10 to 100 per wavelength pixel. We find that for S/N \$\textbackslash geq\$ 50, this technique can yield ages of SSPs to an overall precision of \$\textbackslash Delta\textbackslash,\textbackslash mbox\{log(age/yr)\} \textbackslash sim 0.1\$ for ages in the ranges 7.0 \$\textbackslash leq\$ log (age/yr) \$\textbackslash leq\$ 8.3 and 8.9 \$\textbackslash leq\$ log (age/yr) \$\textbackslash leq\$ 9.4. For the age ranges of 8.3 \$\textbackslash leq\$ log (age/yr) \$\textbackslash leq\$ 8.9 and log (age/yr) \$\textbackslash geq\$ 9.5, which have significant flux contributions from asymptotic giant branch (AGB) and red giant branch (RGB) stars, respectively, the age uncertainty rises to about \$\textbackslash pm 0.3\$ dex. The precision of age and metallicity estimation using this method depends significantly on the S/N and the wavelength range used in the fitting. We quantify the systematic differences in age predicted by the MIST and Padova isochrone models, due to their different assumptions about stellar physics in various important (i.e., luminous) phases of stellar evolution, which needs to be taken in consideration when comparing ages of star clusters obtained using these popular models. Knowing the strengths and limitations of this technique is crucial in interpreting the results obtained for real star clusters and for deciding the optimal instrument setup before performing the observations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\IPHIIKLB\\2008.html}}
@article{ascenso_embedded_2018, title = {Embedded {{Clusters}}}, author = {Ascenso, Joana}, year = {2018}, journal = {The Birth of Star Clusters}, volume = {424}, pages = {1}, doi = {10.1007/978-3-319-22801-3_1}, urldate = {2019-09-20}, abstract = {The past decade has seen an increase of star formation studies made at the molecular cloud scale, motivated mostly by the deployment of a wealth of sensitive infrared telescopes and instruments. Embedded clusters, long recognised as the basic units of coherent star formation in molecular clouds, are now seen to inhabit preferentially cluster complexes tens of parsecs across. This chapter gives an overview of some important properties of the embedded clusters in these complexes and of the complexes themselves, along with the implications of viewing star formation as a molecular-cloud scale process rather than an isolated process at the scale of clusters.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\IYXKU7J6\\abstract.html}}
@article{astropy_collaboration_astropy_2018, title = {The {{Astropy Project}}: {{Building}} an {{Open-science Project}} and {{Status}} of the v2.0 {{Core Package}}}, shorttitle = {The {{Astropy Project}}}, author = {{Astropy Collaboration} and {Price-Whelan}, A. M. and Sip{\H o}cz, B. M. and G{\"u}nther, H. M. and Lim, P. L. and Crawford, S. M. and Conseil, S. and Shupe, D. L. and Craig, M. W. and Dencheva, N. and Ginsburg, A. and VanderPlas, J. T. and Bradley, L. D. and {P{\'e}rez-Su{\'a}rez}, D. and {de Val-Borro}, M. and Aldcroft, T. L. and Cruz, K. L. and Robitaille, T. P. and Tollerud, E. J. and Ardelean, C. and Babej, T. and Bach, Y. P. and Bachetti, M. and Bakanov, A. V. and Bamford, S. P. and Barentsen, G. and Barmby, P. and Baumbach, A. and Berry, K. L. and Biscani, F. and Boquien, M. and Bostroem, K. A. and Bouma, L. G. and Brammer, G. B. and Bray, E. M. and Breytenbach, H. and Buddelmeijer, H. and Burke, D. J. and Calderone, G. and Cano Rodr{\'i}guez, J. L. and Cara, M. and Cardoso, J. V. M. and Cheedella, S. and Copin, Y. and Corrales, L. and Crichton, D. and D'Avella, D. and Deil, C. and Depagne, {\'E}. and Dietrich, J. P. and Donath, A. and Droettboom, M. and Earl, N. and Erben, T. and Fabbro, S. and Ferreira, L. A. and Finethy, T. and Fox, R. T. and Garrison, L. H. and Gibbons, S. L. J. and Goldstein, D. A. and Gommers, R. and Greco, J. P. and Greenfield, P. and Groener, A. M. and Grollier, F. and Hagen, A. and Hirst, P. and Homeier, D. and Horton, A. J. and Hosseinzadeh, G. and Hu, L. and Hunkeler, J. S. and Ivezi{\'c}, {\v Z}. and Jain, A. and Jenness, T. and Kanarek, G. and Kendrew, S. and Kern, N. S. and Kerzendorf, W. E. and Khvalko, A. and King, J. and Kirkby, D. and Kulkarni, A. M. and Kumar, A. and Lee, A. and Lenz, D. and Littlefair, S. P. and Ma, Z. and Macleod, D. M. and Mastropietro, M. and McCully, C. and Montagnac, S. and Morris, B. M. and Mueller, M. and Mumford, S. J. and Muna, D. and Murphy, N. A. and Nelson, S. and Nguyen, G. H. and Ninan, J. P. and N{\"o}the, M. and Ogaz, S. and Oh, S. and Parejko, J. K. and Parley, N. and Pascual, S. and Patil, R. and Patil, A. A. and Plunkett, A. L. and Prochaska, J. X. and Rastogi, T. and Reddy Janga, V. and Sabater, J. and Sakurikar, P. and Seifert, M. and Sherbert, L. E. and {Sherwood-Taylor}, H. and Shih, A. Y. and Sick, J. and Silbiger, M. T. and Singanamalla, S. and Singer, L. P. and Sladen, P. H. and Sooley, K. A. and Sornarajah, S. and Streicher, O. and Teuben, P. and Thomas, S. W. and Tremblay, G. R. and Turner, J. E. H. and Terr{\'o}n, V. and {van Kerkwijk}, M. H. and {de la Vega}, A. and Watkins, L. L. and Weaver, B. A. and Whitmore, J. B. and Woillez, J. and Zabalza, V. and {Astropy Contributors}}, year = {2018}, month = sep, journal = {The Astronomical Journal}, volume = {156}, pages = {123}, issn = {0004-6256}, doi = {10.3847/1538-3881/aabc4f}, urldate = {2020-06-24}, abstract = {The Astropy Project supports and fosters the development of open-source and openly developed Python packages that provide commonly needed functionality to the astronomical community. A key element of the Astropy Project is the core package astropy, which serves as the foundation for more specialized projects and packages. In this article, we provide an overview of the organization of the Astropy project and summarize key features in the core package, as of the recent major release, version 2.0. We then describe the project infrastructure designed to facilitate and support development for a broader ecosystem of interoperable packages. We conclude with a future outlook of planned new features and directions for the broader Astropy Project. .}, keywords = {methods: data analysis,methods: miscellaneous,methods: statistical,reference systems}}
@article{bailer-jones_estimating_2018, title = {Estimating {{Distance}} from {{Parallaxes}}. {{IV}}. {{Distances}} to 1.33 {{Billion Stars}} in {{Gaia Data Release}} 2}, author = {{Bailer-Jones}, C. A. L. and Rybizki, J. and Fouesneau, M. and Mantelet, G. and Andrae, R.}, year = {2018}, month = jul, journal = {The Astronomical Journal}, volume = {156}, number = {2}, pages = {58}, issn = {1538-3881}, doi = {10.3847/1538-3881/aacb21}, urldate = {2020-01-09}, abstract = {For the vast majority of stars in the second Gaia data release, reliable distances cannot be obtained by inverting the parallax. A correct inference procedure must instead be used to account for the nonlinearity of the transformation and the asymmetry of the resulting probability distribution. Here, we infer distances to essentially all 1.33 billion stars with parallaxes published in the second Gaia data release. This is done using a weak distance prior that varies smoothly as a function of Galactic longitude and latitude according to a Galaxy model. The irreducible uncertainty in the distance estimate is characterized by the lower and upper bounds of an asymmetric confidence interval. Although more precise distances can be estimated for a subset of the stars using additional data (such as photometry), our goal is to provide purely geometric distance estimates, independent of assumptions about the physical properties of, or interstellar extinction toward, individual stars. We analyze the characteristics of the catalog and validate it using clusters. The catalog can be queried using ADQL at http://gaia.ari.uni-heidelberg.de/tap.html (which also hosts the Gaia catalog) and downloaded from http://www.mpia.de/ calj/gdr2\_distances.html.}, langid = {english}, keywords = {read}}
@article{bailer-jones_estimating_2021, title = {Estimating Distances from Parallaxes. {{V}}: {{Geometric}} and Photogeometric Distances to 1.47 Billion Stars in {{Gaia Early Data Release}} 3}, shorttitle = {Estimating Distances from Parallaxes. {{V}}}, author = {{Bailer-Jones}, C. A. L. and Rybizki, J. and Fouesneau, M. and Demleitner, M. and Andrae, R.}, year = {2021}, month = mar, journal = {The Astronomical Journal}, volume = {161}, number = {3}, pages = {147}, urldate = {2020-12-11}, abstract = {Stellar distances constitute a foundational pillar of astrophysics. The publication of 1.47 billion stellar parallaxes from Gaia is a major contribution to this. Yet despite Gaia's precision, the majority of these stars are so distant or faint that their fractional parallax uncertainties are large, thereby precluding a simple inversion of parallax to provide a distance. Here we take a probabilistic approach to estimating stellar distances that uses a prior constructed from a three-dimensional model of our Galaxy. This model includes interstellar extinction and Gaia's variable magnitude limit. We infer two types of distance. The first, geometric, uses the parallax together with a direction-dependent prior on distance. The second, photogeometric, additionally uses the colour and apparent magnitude of a star, by exploiting the fact that stars of a given colour have a restricted range of probable absolute magnitudes (plus extinction). Tests on simulated data and external validations show that the photogeometric estimates generally have higher accuracy and precision for stars with poor parallaxes. We provide a catalogue of 1.47 billion geometric and 1.35 billion photogeometric distances together with asymmetric uncertainty measures. Our estimates are quantiles of a posterior probability distribution, so they transform invariably and can therefore also be used directly in the distance modulus (5log10(r)-5). The catalogue may be downloaded or queried using ADQL at various sites (see http://www.mpia.de/homes/calj/gedr3\_distances.html) where it can also be cross-matched with the Gaia catalogue.}, keywords = {\_tablet,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5XRCGB23\\2012.html}}
@article{bailer-jones_inference_2018, title = {Inference of Cluster Distance and Geometry from Astrometry}, author = {{Bailer-Jones}, Coryn A L}, year = {2018}, pages = {5}, abstract = {Here I outline a method to determine the distance to and size/shape of a stellar cluster given measurements of the parallaxes and sky positions of (some of) its cluster members. I start rather generally, but then proceed to make some simplyfing assumptions. This example also serves to illustrate the key steps involved in solving many general parameter inference problems.}, langid = {english}, keywords = {Bayesian Statistics Guide,Open Cluster Guide,Read}, file = {/home/ehunt/Zotero/storage/GUWCGUHP/Bailer-Jones_2018_Inference of cluster distance and geometry from astrometry_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\GUWCGUHP\\Bailer-Jones_2018_Inference of cluster distance and geometry from astrometry.pdf}}
@article{balaguer-nunez_clusterix_2020, title = {Clusterix 2.0: A Virtual Observatory Tool to Estimate Cluster Membership Probability}, shorttitle = {Clusterix 2.0}, author = {{Balaguer-N{\'u}{\~n}ez}, L. and {L{\'o}pez del Fresno}, M. and Solano, E. and {Galad{\'i}-Enr{\'i}quez}, D. and Jordi, C. and {Jimenez-Esteban}, F. and Masana, E. and {Carbajo-Hijarrubia}, J. and Paunzen, E.}, year = {2020}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {492}, pages = {5811--5843}, issn = {0035-8711}, doi = {10.1093/mnras/stz3610}, urldate = {2020-03-19}, abstract = {Clusterix 2.0 is a web-based, Virtual Observatory compliant, interactive tool for the determination of membership probabilities in stellar clusters based on proper-motion data using a fully non-parametric method. In an area occupied by a cluster, the frequency function is made up of two contributions: cluster and field stars. The tool performs an empirical determination of the frequency functions from the vector point diagram without relying on any previous assumption about their profiles. Clusterix 2.0 allows us to search the appropriate spatial areas in an interactive way until an optimal separation of the two populations is obtained. Several parameters can be adjusted to make the calculation computationally feasible without interfering with the quality of the results. The system offers the possibility to query different catalogues, such as Gaia, or upload a user's own data. The results of the membership determination can be sent via Simple Application Messaging Protocol (SAMP) to Virtual Observatory (VO) tools such as Tool for OPerations on Catalogues And Tables (TOPCAT). We apply Clusterix 2.0 to several open clusters with different properties and environments to show the capabilities of the tool: an area of five degrees radius around NGC 2682 (M67), an old, well-known cluster; a young cluster NGC 2516 with a striking elongated structure extended up to four degrees; NGC 1750 and NGC 1758, a pair of partly overlapping clusters; the area of NGC 1817, where we confirm a little-known cluster, Juchert 23; and an area with many clusters, where we disentangle two overlapping clusters situated where only one was previously known: Ruprecht 26 and the new CLUSTERIX 1.}, keywords = {Clusterix 1,methods: statistical,open clusters and associations: general,open clusters and associations: individual: NGC 2682,proper motions,virtual observatory tools}}
@article{ballone_evolution_2020, title = {Evolution of Fractality and Rotation in Embedded Star Clusters}, author = {Ballone, Alessandro and Mapelli, Michela and Di Carlo, Ugo N. and Torniamenti, Stefano and Spera, Mario and Rastello, Sara}, year = {2020}, month = jan, journal = {arXiv:2001.10003 [astro-ph]}, eprint = {2001.10003}, primaryclass = {astro-ph}, urldate = {2020-01-29}, abstract = {More and more observations indicate that young star clusters could retain imprints of their formation process. In particular, the degree of substructuring and rotation are possibly the direct result of the collapse of the parent molecular cloud from which these systems form. Such properties can, in principle, be washed-out, but they are also expected to have an impact on the relaxation of these systems. We ran and analyzed a set of ten hydrodynamical simulations of the formation of embedded star clusters through the collapse of turbulent massive molecular clouds. We systematically studied the fractality of our star clusters, showing that they are all extremely substructured (fractal dimension \$D=1.0-1.8\$). We also found that fractality is slowly reduced, with time, on small scales, while it persists on large scales on longer timescales. Signatures of rotation are found in different simulations at every time of the evolution, even for slightly supervirial substructures, proving that the parent molecular gas transfers part of its angular momentum to the new stellar systems.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Z4BBKEZ2\\2001.html}}
@article{banerjee_how_2017, title = {How Can Young Massive Clusters Reach Their Present-Day Sizes?}, author = {Banerjee, Sambaran and Kroupa, Pavel}, year = {2017}, month = jan, journal = {Astronomy and Astrophysics}, volume = {597}, pages = {A28}, issn = {0004-6361}, doi = {10.1051/0004-6361/201526928}, urldate = {2021-10-28}, abstract = {Context. The classic question of how young massive star clusters attain the shapes and sizes, as we find them today, is still a difficult one. Both observational and computational studies of star-forming massive molecular gas clouds suggest that massive cluster formation is primarily triggered along the small-scale ({$\lessequivlnt$}0.3 pc) filamentary substructures within the clouds. {$<$}BR /{$>$} Aims: The present study investigates the possible ways in which a filament-like, compact, massive star cluster (effective radius 0.1-0.3 pc) can expand more than 10 times, still remaining massive enough ({$\greaterequivlnt$} 10\textsuperscript{4}M\textsubscript{{$\odot$}}) to become the young massive star cluster that we observe today. {$<$}BR /{$>$} Methods: To this end, model massive clusters (initially 10\textsuperscript{4}-10\textsuperscript{5}M\textsubscript{{$\odot$}}) are evolved using Sverre Aarseth's state-of-the-art N-body code NBODY7. Apart from the accurate calculation of two-body relaxation of the constituent stars, these evolutionary models take into account stellar-evolutionary mass loss and dynamical energy injection due to massive, tight primordial binaries and stellar-remnant black holes and neutron stars. These calculations also include a solar-neighbourhood-like external tidal field. All the computed clusters expand with time, and their sizes (effective radii) are compared with those observed for young massive clusters ({$\lessequivlnt$} 100 Myr) in the Milky Way and other nearby galaxies. {$<$}BR /{$>$} Results: In this study, it is found that beginning from the above compact sizes, a star cluster cannot expand on its own, I.e., due to two-body relaxation, stellar mass loss, and dynamical heating by primordial binaries and compact stars up to the observed sizes of young massive clusters; star clusters always remain much more compact than the observed ones. {$<$}BR /{$>$} Conclusions: This calls for additional mechanisms that boost the expansion of a massive cluster after its assembly. Using further N-body calculations, it is shown that a substantial residual gas expulsion with {$\approx$} 30\% star formation efficiency can indeed swell the newborn embedded cluster adequately. The limitations of the present calculations and their consequences are discussed.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\I7CVFLVN\\abstract.html}}
@article{banerjee_lisa_2020, title = {{{LISA}} Sources from Young Massive and Open Stellar Clusters}, author = {Banerjee, Sambaran}, year = {2020}, month = sep, journal = {arXiv:2006.14587 [astro-ph]}, eprint = {2006.14587}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {I study the potential role of young massive (YMCs) and open star clusters (OCs) in assembling stellar-mass binary black holes (BBHs) which would be detectable as persistent gravitational-wave (GW) sources by the forthcoming LISA mission. The energetic dynamical interactions inside star clusters make them factories of assembling BBHs and other types of double-compact binaries that undergo general-relativistic (GR) inspiral and merger. The initial phase of such inspirals would, typically, sweep through the LISA GW band. Here, such LISA sources are studied from a set of evolutionary models of star clusters with masses ranging over \$10\^4M\_\textbackslash odot-10\^5M\_\textbackslash odot\$ that represent YMCs and intermediate-aged OCs in metal-rich and metal-poor environments of the Local Universe. These models are evolved with long-term, direct, relativistic many-body computations incorporating state-of-the-art stellar-evolutionary and remnant-formation models. Based on models of Local Universe constructed with such model clusters, it is shown that YMCs and intermediate-aged OCs would yield several 10s to 100s of LISA BBH sources at the current cosmic epoch with GW frequency within \$10\^\{-3\}\{\textbackslash rm\textasciitilde Hz\} - 10\^\{-1\}\{\textbackslash rm\textasciitilde Hz\}\$ and signal-to-noise-ratio (S/N) \${$>$}5\$, assuming a mission lifetime of 5 or 10 years. Such LISA BBHs would have a bimodal distribution in total mass, be generally eccentric (\$\textbackslash lesssim0.7\$), and typically have similar component masses although mass-asymmetric systems are possible. Intrinsically, there would be 1000s of present-day, LISA-detectable BBHs from YMCs and OCs. That way, YMCs and OCs would provide a significant and the dominant contribution to the stellar-mass BBH population detectable by LISA. A small fraction, \${$<$}5\$\%, of these BBHs would undergo GR inspiral to make it to LIGO-Virgo GW frequency band and merge, within the mission timespan; \${$<$}15\$\% would do so within twice the timespan.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - High Energy Astrophysical Phenomena}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M5EJCNP2\\2006.html}}
@article{baratella_gaia-eso_2020, title = {The {{Gaia-ESO Survey}}: A New Approach to Chemically Characterising Young Open Clusters. {{I}}. {{Stellar}} Parameters, and Iron-Peak, {$\alpha$}-, and Proton-Capture Elements}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Baratella, M. and D'Orazi, V. and Carraro, G. and Desidera, S. and Randich, S. and Magrini, L. and Adibekyan, V. and Smiljanic, R. and Spina, L. and Tsantaki, M. and Tautvai{\v s}ien{\.e}, G. and Sousa, S. G. and Jofr{\'e}, P. and {Jim{\'e}nez-Esteban}, F. M. and {Delgado-Mena}, E. and Martell, S. and {Van der Swaelmen}, M. and Roccatagliata, V. and Gilmore, G. and Alfaro, E. J. and Bayo, A. and Bensby, T. and Bragaglia, A. and Franciosini, E. and Gonneau, A. and Heiter, U. and Hourihane, A. and Jeffries, R. D. and Koposov, S. E. and Morbidelli, L. and Prisinzano, L. and Sacco, G. and Sbordone, L. and Worley, C. and Zaggia, S. and Lewis, J.}, year = {2020}, month = feb, journal = {Astronomy and Astrophysics}, volume = {634}, pages = {A34}, issn = {0004-6361}, doi = {10.1051/0004-6361/201937055}, urldate = {2023-02-28}, abstract = {Context. Open clusters are recognised as excellent tracers of Galactic thin-disc properties. At variance with intermediate-age and old open clusters, for which a significant number of studies is now available, clusters younger than {$\lessequivlnt$}150 Myr have been mostly overlooked in terms of their chemical composition until recently (with few exceptions). On the other hand, previous investigations seem to indicate an anomalous behaviour of young clusters, which includes (but is not limited to) slightly sub-solar iron (Fe) abundances and extreme, unexpectedly high barium (Ba) enhancements. {$<$}BR /{$>$} Aims: In a series of papers, we plan to expand our understanding of this topic and investigate whether these chemical peculiarities are instead related to abundance analysis techniques. {$<$}BR /{$>$} Methods: We present a new determination of the atmospheric parameters for 23 dwarf stars observed by the Gaia-ESO survey in five young open clusters ({$\tau$} \< 150 Myr) and one star-forming region (NGC 2264). We exploit a new method based on titanium (Ti) lines to derive the spectroscopic surface gravity, and most importantly, the microturbulence parameter. A combination of Ti and Fe lines is used to obtain effective temperatures. We also infer the abundances of Fe I, Fe II, Ti I, Ti II, Na I, Mg I, Al I, Si I, Ca I, Cr I, and Ni I. {$<$}BR /{$>$} Results: Our findings are in fair agreement with Gaia-ESO iDR5 results for effective temperatures and surface gravities, but suggest that for very young stars, the microturbulence parameter is over-estimated when Fe lines are employed. This affects the derived chemical composition and causes the metal content of very young clusters to be under-estimated. {$<$}BR /{$>$} Conclusions: Our clusters display a metallicity [Fe/H] between +0.04 {$\pm$} 0.01 and +0.12 {$\pm$} 0.02; they are not more metal poor than the Sun. Although based on a relatively small sample size, our explorative study suggests that we may not need to call for ad hoc explanations to reconcile the chemical composition of young open clusters with Galactic chemical evolution models. {$<$}P /{$>$}Full Table 2 is only available at the CDS via anonymous ftp to {$<$}A href="http://cdsarc.u-strasbg.fr"{$>$}http://cdsarc.u-strasbg.fr{$<$}/A{$>$} (ftp://130.79.128.5) or via {$<$}A href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/634/A34"{$>$}http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/634/A34{$<$}/A{$>$} {$<$}P /{$>$}Based on observations collected with the FLAMES instrument at VLT/UT2 telescope (Paranal Observatory, ESO, Chile), for the Gaia- ESO Large Public Spectroscopic Survey (188.B-3002, 193.B-0936).}, langid = {english}}
@article{bastian_effect_stellar_2009, title = {The Effect of Stellar Rotation on Colour-Magnitude Diagrams: On the Apparent Presence of Multiple Populations in Intermediate Age Stellar Clusters}, author = {Bastian, N. and {de Mink}, S. E.}, year = {2009}, month = sep, volume = {398}, number = {1}, eprint = {0906.1590}, primaryclass = {astro-ph.GA}, pages = {L11-L15}, doi = {10.1111/j.1745-3933.2009.00696.x}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,galaxies: star clusters,stars: rotation}}
@article{bastian_gaia_2019, title = {Gaia 8: {{Discovery}} of a Star Cluster Containing {$\beta$} {{Lyrae}}}, shorttitle = {Gaia 8}, author = {Bastian, U.}, year = {2019}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {630}, pages = {L8}, issn = {0004-6361}, doi = {10.1051/0004-6361/201936595}, urldate = {2022-03-28}, abstract = {{$<$}BR /{$>$} Aims: The aim here is to try and clarify whether there are stars in the neighbourhood of {$\beta$} Lyrae which are physically connected to the famous prototype eclipsing binary. {$<$}BR /{$>$} Methods: We scrutinised the astrometric and photometric data (from HIPPARCOS and Gaia DR2) of stars in a limited sky field around {$\beta$} Lyrae. {$<$}BR /{$>$} Results: A star cluster of about 100 members was discovered, nicely centred on {$\beta$} Lyrae in five dimensions. There are clear indications that the newly discovered cluster belongs to a larger old (extinct) star formation complex, including two known star clusters and an extended, strewn field of stars at practically the same distance and space velocity. {$<$}BR /{$>$} Conclusions: This discovery opens up the possibility of determining a precise distance and precise age for {$\beta$} Lyrae using the combined properties of the cluster members. This in turn may form an important basis for an improved astrophysical interpretation of the model binary {$\beta$} Lyrae and its kin. The larger old star formation complex is of scientific interest in its own right.}, langid = {english}}
@article{baumgardt_absolute_2020, title = {Absolute {{V-band}} Magnitudes and Mass-to-Light Ratios of {{Galactic}} Globular Clusters}, author = {Baumgardt, H. and Sollima, A. and Hilker, M.}, year = {2020}, month = sep, journal = {arXiv:2009.09611 [astro-ph]}, eprint = {2009.09611}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {We have used HST and ground-based photometry to determine total \$V\$-band magnitudes and mass-to-light ratios of more than 150 Galactic globular clusters. We do this by summing up the magnitudes of their individual member stars, using color-magnitude information, Gaia DR2 proper motions and radial velocities to distinguish cluster stars from background stars. Our new magnitudes confirm literature estimates for bright clusters with V{$<$}8, but can deviate by up to two magnitudes from literature values for fainter clusters. They lead to absolute mass-to-light ratios that are confined to the narrow range 1.4}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@misc{baumgardt_evidence_2023, title = {Evidence for a Bottom-Light Initial Mass Function in Massive Star Clusters}, author = {Baumgardt, Holger and {Henault-Brunet}, Vincent and Dickson, Nolan and Sollima, Antonio}, year = {2023}, month = mar, number = {arXiv:2303.01636}, eprint = {2303.01636}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.01636}, urldate = {2023-03-07}, abstract = {We have determined stellar mass functions of 120 Milky Way globular clusters and massive LMC/SMC star clusters based on a comparison of archival Hubble Space Telescope photometry with a large grid of direct N-body simulations. We find a strong correlation of the global mass function slopes of star clusters with both their internal relaxation times as well as their lifetimes. Once dynamical effects are being accounted for, the mass functions of most star clusters are compatible with an initial mass function described by a broken power-law distribution \$N(m) \textbackslash sim m\^\textbackslash alpha\$ with break masses at 0.4 M\$\_\textbackslash odot\$ and 1.0 M\$\_\textbackslash odot\$ and mass function slopes of \$\textbackslash alpha\_\{Low\}=-0.3\$ for stars with masses \$m{$<$}0.4\$ M\$\_\textbackslash odot\$, \$\textbackslash alpha\_\{High\}=-2.30\$ for stars with \$m{$>$}1.0\$ M\$\_\textbackslash odot\$ and \$\textbackslash alpha\_\{Med\}=-1.65\$ for intermediate-mass stars. Alternatively, a log-normal mass function with a characteristic mass \$\textbackslash log M\_C = -0.36\$ and width \$\textbackslash sigma\_C=0.28\$ for low-mass stars and a power-law mass function for stars with \$m{$>$}1\$ M\$\_\textbackslash odot\$ also fits our data. We do not find a significant environmental dependency of the initial mass function with either cluster mass, density, global velocity dispersion or metallicity. Our results lead to a larger fraction of high-mass stars in globular clusters compared to canonical Kroupa/Chabrier mass functions, increasing the efficiency of self-enrichment in clusters and helping to alleviate the mass budget problem of multiple stellar populations in globular clusters. By comparing our results with direct N-body simulations we finally find that only simulations in which most black holes are ejected by natal birth kicks correctly reproduce the observed correlations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{beccari_uncovering_2020, title = {Uncovering a 260 Pc Wide, 35-{{Myr-old}} Filamentary Relic of Star Formation}, author = {Beccari, Giacomo and Boffin, Henri M. J. and Jerabkova, Tereza}, year = {2020}, month = jan, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {491}, pages = {2205--2216}, issn = {0035-8711}, doi = {10.1093/mnras/stz3195}, urldate = {2021-10-28}, abstract = {Several recent studies have shown that the Vela OB2 region hosts a complex constellation of sub-populations with ages in the range 10 to 50 Myr. Such populations might represent the best example of the outcome of clustered star formation in giant molecular clouds (GMCs). We use Gaia DR2 data over an area of 40 deg radius around the open cluster Collinder 135 to extend the study of the stellar populations of the Vela OB2 region over an area of several hundreds of parsecs on sky. Detailed clustering algorithms combined with the exquisite astrometric quality of the Gaia catalogue allow us to detect a new cluster named BBJ 1 that shows the same age as NGC 2547 (30 to 35 Myr), but located at a distance of 260 pc from it. Deeper investigation of the region via clustering in 5D parameter space and in the colour-magnitude diagram allows us to detect a filamentary structure of stars that bridges the two clusters. Given the extent in space of such structure (260 pc) and the young age ({$\sim$}35 Myr), we exclude that such population originates by the same mechanism responsible to create tidal streams around older clusters. Even if we miss a complete picture of the 3D motion of the studied stellar structure because of the lack of accurate radial velocity measurements, we propose that such structure represents the detection of a 35-Myr-old outcome of a mechanism of filamentary star formation in a GMC.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general,stars: formation,stars: pre-main-sequence}, annotation = {ADS Bibcode: 2020MNRAS.491.2205B}}
@article{becker_cnn_2021, title = {{{CNN Architecture Comparison}} for {{Radio Galaxy Classification}}}, author = {Becker, Burger and Vaccari, Mattia and Prescott, Matthew and Grobler, Trienko Lups}, year = {2021}, month = feb, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {503}, number = {2}, pages = {1828--1846}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stab325}, urldate = {2021-02-10}, abstract = {The morphological classification of radio sources is important to gain a full understanding of galaxy evolution processes and their relation with local environmental properties. Furthermore, the complex nature of the problem, its appeal for citizen scientists and the large data rates generated by existing and upcoming radio telescopes combine to make the morphological classification of radio sources an ideal test case for the application of machine learning techniques. One approach that has shown great promise recently is Convolutional Neural Networks (CNNs). Literature, however, lacks two major things when it comes to CNNs and radio galaxy morphological classification. Firstly, a proper analysis of whether overfitting occurs when training CNNs to perform radio galaxy morphological classification using a small curated training set is needed. Secondly, a good comparative study regarding the practical applicability of the CNN architectures in literature is required. Both of these shortcomings are addressed in this paper. Multiple performance metrics are used for the latter comparative study, such as inference time, model complexity, computational complexity and mean per class accuracy. As part of this study we also investigate the effect that receptive field, stride length and coverage has on recognition performance. For the sake of completeness, we also investigate the recognition performance gains that we can obtain by employing classification ensembles. A ranking system based upon recognition and computational performance is proposed. MCRGNet, Radio Galaxy Zoo and ConvXpress (novel classifier) are the architectures that best balance computational requirements with recognition performance.}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\I4PDCLNL\\2102.html}}
@article{bellagamba_amico:_2018, title = {{{AMICO}}: Optimized Detection of Galaxy Clusters in Photometric Surveys}, shorttitle = {{{AMICO}}}, author = {Bellagamba, Fabio and Roncarelli, Mauro and Maturi, Matteo and Moscardini, Lauro}, year = {2018}, month = feb, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {473}, number = {4}, pages = {5221--5236}, issn = {0035-8711}, doi = {10.1093/mnras/stx2701}, urldate = {2019-11-04}, abstract = {Abstract. We present Adaptive Matched Identifier of Clustered Objects (AMICO), a new algorithm for the detection of galaxy clusters in photometric surveys. AMI}, langid = {english}, keywords = {Clustering Algorithm,Read}}
@article{bellet_survey_2014, title = {A {{Survey}} on {{Metric Learning}} for {{Feature Vectors}} and {{Structured Data}}}, author = {Bellet, Aur{\'e}lien and Habrard, Amaury and Sebban, Marc}, year = {2014}, month = feb, journal = {arXiv:1306.6709 [cs, stat]}, eprint = {1306.6709}, primaryclass = {cs, stat}, urldate = {2020-02-05}, abstract = {The need for appropriate ways to measure the distance or similarity between data is ubiquitous in machine learning, pattern recognition and data mining, but handcrafting such good metrics for specific problems is generally difficult. This has led to the emergence of metric learning, which aims at automatically learning a metric from data and has attracted a lot of interest in machine learning and related fields for the past ten years. This survey paper proposes a systematic review of the metric learning literature, highlighting the pros and cons of each approach. We pay particular attention to Mahalanobis distance metric learning, a well-studied and successful framework, but additionally present a wide range of methods that have recently emerged as powerful alternatives, including nonlinear metric learning, similarity learning and local metric learning. Recent trends and extensions, such as semi-supervised metric learning, metric learning for histogram data and the derivation of generalization guarantees, are also covered. Finally, this survey addresses metric learning for structured data, in particular edit distance learning, and attempts to give an overview of the remaining challenges in metric learning for the years to come.}, archiveprefix = {arxiv}, langid = {english}, keywords = {\_tablet,Computer Science - Artificial Intelligence,Computer Science - Machine Learning,Statistics - Machine Learning}}
@misc{bhat_new_2023, title = {New Parameters for Star Cluster Dynamics: The Effect of Primordial Binaries and Dark Remnants}, shorttitle = {New Parameters for Star Cluster Dynamics}, author = {Bhat, Bhavana and Lanzoni, Barbara and Ferraro, Francesco R. and Vesperini, Enrico}, year = {2023}, month = jan, number = {arXiv:2301.07706}, eprint = {2301.07706}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2301.07706}, urldate = {2023-02-13}, abstract = {By studying the normalized cumulative radial distribution (nCRD) of the stars in the central region of a Monte Carlo-simulated globular cluster, we recently defined three parameters able to pinpoint the stage of internal dynamical evolution reached by the system: \$A\_5\$ (i.e., the area subtended by the nCRD within 5\$\textbackslash\%\$ the half-mass radius, \$r\_h\$), \$P\_5\$ (the value of the nCRD at 5\$\textbackslash\%\$ \$r\_h\$), and \$S\_\{2.5\}\$ (the slope of the nCRD at 2.5\$\textbackslash\%\$ \$r\_h\$). Here we extend the analysis and explore the effects that different fractions (0\$\textbackslash\%\$, 10\$\textbackslash\%\$, and 20\$\textbackslash\%\$) of primordial binaries and stellar-mass black holes (BHs) induce on the dynamical history of the system. As expected, the gradual contraction of the cluster becomes milder and core collapse shallower for increasing binary fraction. Nevertheless, the cluster dynamical evolution is still properly traced by the three parameters. For models with a larger initial retention of stellar mass BHs the evolution depends on the timescale of their subsequent dynamical ejection. An early dynamical ejection of BHs results in a long-term evolution of the three parameters similar to that found in systems with no initial BH retention. Conversely, in the model that retains a large number of BHs for extended time (slow dynamical ejection of BHs), the system is characterized by a less concentrated structure and by the lack of significant temporal evolution of the three parameters. The smaller values of the three parameters found in this case might be used to indirectly infer the possible presence of BHs in the cluster.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@misc{bhattacharya_gaia_2022, title = {A \${{Gaia}}\$ {{EDR3}} Search for Tidal Tails in Disintegrating Open Clusters}, author = {Bhattacharya, Souradeep and Rao, Khushboo K. and Agarwal, Manan and Balan, Shanmugha and Vaidya, Kaushar}, year = {2022}, month = sep, number = {arXiv:2209.08259}, eprint = {2209.08259}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2209.08259}, urldate = {2022-09-22}, abstract = {We carry out a search for tidal tails in a sample of open clusters with known relatively elongated morphology. We identify the member stars of these clusters from the precise astrometric and deep photometric data from \$Gaia\$ Early Data Release 3 using the robust membership determination algorithm, ML-MOC. We identify 46 open clusters having a stellar corona beyond the tidal radius, 20 of which exhibit extended tails aligned with the cluster orbit direction in galactocentric coordinates. Notably we find NGC 6940 (at a distance of \$\textbackslash sim1\$ kpc) is the furthest open cluster exhibiting tidal tails that are \$\textbackslash sim50\$ pc from its center, while also identifying \$\textbackslash sim40\$ pc long tidal tails for the nearby Pleiades. Using the minimum spanning tree length for the most massive stars relative to all cluster members, we obtain the mass segregation ratio (\$\textbackslash rm\textbackslash lambda\_\{MSR\}\$) profiles as a function of the number of massive stars in each cluster. From these profiles, we can classify the open clusters into four classes based on the degree of mass segregation experienced by the clusters. We find that clusters in the most mass segregated classes are the oldest on average and have the flattest mass function slope. Of the 46 open clusters studied in this work, 41 exhibit some degree of mass segregation. Furthermore, we estimate the initial masses (M\$\textbackslash rm\_\{i\}\$) of these open clusters finding that some of them, having M\$\textbackslash rm\_\{i\}\textbackslash gtrsim 10\^\{4\} M\_\{\textbackslash odot\}\$, could be the dissolving remnants of Young Massive Clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{bialopetravicius_deriving_2019, title = {Deriving Star Cluster Parameters with Convolutional Neural Networks. {{II}}. {{Extinction}} and Cluster/Background Classification}, author = {Bialopetravi{\v c}ius, J. and Narbutis, D. and Vansevi{\v c}ius, V.}, year = {2019}, month = nov, journal = {arXiv:1911.10059 [astro-ph]}, eprint = {1911.10059}, primaryclass = {astro-ph}, urldate = {2019-11-25}, abstract = {Context. Convolutional neural networks (CNNs) have been established as the go-to method for fast object detection and classification on natural images. This opens the door for astrophysical parameter inference on the exponentially increasing amount of sky survey data. Until now, star cluster analysis was based on integral or resolved stellar photometry, which limits the amount of information that can be extracted from individual pixels of cluster images. Aims. We aim to create a CNN capable of inferring star cluster evolutionary, structural, and environmental parameters from multi-band images, as well to demonstrate its capabilities in discriminating genuine clusters from galactic stellar backgrounds. Methods. A CNN based on the deep residual network (ResNet) architecture was created and trained to infer cluster ages, masses, sizes, and extinctions, with respect to the degeneracies between them. Mock clusters placed on M83 Hubble Space Telescope (HST) images utilizing three photometric passbands (F336W, F438W, and F814W) were used. The CNN is also capable of predicting the likelihood of a cluster's presence in an image, as well as quantifying its visibility (signal-to-noise). Results. The CNN was tested on mock images of artificial clusters and has demonstrated reliable inference results for clusters of ages \$\textbackslash lesssim\$100 Myr, extinctions \$A\_V\$ between 0 and 3 mag, masses between \$3\textbackslash times10\^3\$ and \$3\textbackslash times10\^5\$ \$\{\textbackslash rm M\_\textbackslash odot\}\$, and sizes between 0.04 and 0.4 arcsec at the distance of the M83 galaxy. Real M83 galaxy cluster parameter inference tests were performed with objects taken from previous studies and have demonstrated consistent results.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Computer Science - Computer Vision and Pattern Recognition}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GR7DYMS7\\1911.html}}
@article{bialopetravicius_study_2020, title = {Study of Star Clusters in the {{M83}} Galaxy with a Convolutional Neural Network}, author = {Bialopetravi{\v c}ius, J. and Narbutis, D.}, year = {2020}, month = oct, journal = {arXiv:2010.11126 [astro-ph]}, eprint = {2010.11126}, primaryclass = {astro-ph}, urldate = {2020-10-22}, abstract = {We present a study of evolutionary and structural parameters of star cluster candidates in the spiral galaxy M83. For this we use a convolutional neural network trained on mock clusters and capable of fast identification and localization of star clusters, as well as inference of their parameters from multi-band images. We use this pipeline to detect 3,380 cluster candidates in Hubble Space Telescope observations. The sample of cluster candidates shows an age gradient across the galaxy's spiral arms, which is in good agreement with predictions of the density wave theory and other studies. As measured from the dust lanes of the spiral arms, the younger population of cluster candidates peaks at the distance of \$\textbackslash sim\$0.4 kpc while the older candidates are more dispersed, but shifted towards \$\textbackslash gtrsim\$0.7 kpc in the leading part of the spiral arms. We find high extinction cluster candidates positioned in the trailing part of the spiral arms, close to the dust lanes. We also find a large number of dense older clusters near the center of the galaxy and a slight increase of the typical cluster size further from the center.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Computer Science - Computer Vision and Pattern Recognition}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Y3NM29WW\\2010.html}}
@article{bica_general_2008, title = {A General Catalogue of Extended Objects in the {{Magellanic System}}}, author = {Bica, E. and Bonatto, C. and Dutra, C. M. and Santos, J. F. C.}, year = {2008}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {389}, pages = {678--690}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2008.13612.x}, urldate = {2022-03-28}, abstract = {We update the Small Magellanic Cloud (SMC), Bridge and Large Magellanic Cloud (LMC) catalogues of extended objects that were constructed by members of our group from 1995 to 2000. In addition to the rich subsequent literature for the previous classes, we now also include HI shells and supershells. A total of 9305 objects were cross-identified, while our previous catalogues amounted to 7900 entries, an increase of \textasciitilde 12 per cent. We present the results in subcatalogues containing 1445 emission nebulae, 3740 star clusters, 3326 associations and 794 HI shells and supershells. Angular and apparent size distributions of the extended objects are analysed. We conclude that the objects, in general, appear to respond to tidal effects arising from the LMC, SMC and Bridge. Number-density profiles extracted along directions parallel and perpendicular to the LMC bar, can be described by two exponential-discs. A single exponential-disc fits the equivalent SMC profiles. Interestingly, when angular-averaged number-densities of most of the extended objects are considered, the profiles of both Clouds do not follow an exponential-disc. Rather, they are best described by a tidally truncated, core/halo profile, despite the fact that the Clouds are clearly disturbed discs. On the other hand, the older star clusters taken isolately, distribute as an exponential disc. The present catalogue is an important tool for the unambiguous identification of previous objects in current CCD surveys and to establish new findings.}, keywords = {Astrophysics,Magellanic Clouds}}
@article{bica_multi-band_2018, title = {A {{Multi-band Catalog}} of 10978 {{Star Clusters}}, {{Associations}}, and {{Candidates}} in the {{Milky Way}}}, author = {Bica, Eduardo and Pavani, Daniela B. and Bonatto, Charles J. and Lima, Eliade F.}, year = {2018}, month = dec, journal = {The Astronomical Journal}, volume = {157}, number = {1}, pages = {12}, issn = {1538-3881}, doi = {10.3847/1538-3881/aaef8d}, urldate = {2019-09-30}, abstract = {We present a catalog of Galactic star clusters, associations and candidates with 10978 entries. This multi-band catalog was constructed over 20 years, starting with visual inspections on the Digital Sky Survey and incremented with the 2MASS, WISE, VVV, Spitzer, and Herschel surveys. Large and small catalogs, as well as papers on individual objects have been systematically cross-identified. The catalog provides Galactic and equatorial coordinates, angular diameters, and chronologically ordered designations, making it simple to assign discoveries and verify how often the objects were cataloged by different authors, search methods, and/or surveys. Detection in a single band is the minimum constraint to validate an entry. About 3200 objects have measured parameters in the literature. A fundamental contribution of the present study is to present an additional {$\approx$}7700 objects for the first analyses of nature, photometry, spectroscopy and structure. The present focus is not to compile or determine fundamental parameters, but to provide a catalog uniformly characterizing the entries. A major result is that now 4234 embedded clusters are cataloged, a factor of {$\approx$}1.5 larger than open clusters. In addition to cross-identifications in different references and wavelength domains, we also communicate the discovery of 638 star clusters and similar objects. The present general catalog provides previously studied objects and thousands of additional entries in a homogeneous way, a timely contribution to Gaia-related works.}, langid = {english}, keywords = {Read}}
@article{bica_new_infrared_2003, title = {New Infrared Star Clusters in the {{Northern}} and {{Equatorial Milky Way}} with {{2MASS}}}, author = {Bica, E. and Dutra, C. M. and Soares, J. and Barbuy, B.}, year = {2003}, month = jun, journal = {Astronomy and Astrophysics}, volume = {404}, pages = {223--232}, issn = {0004-6361}, doi = {10.1051/0004-6361:20030486}, urldate = {2023-04-06}, abstract = {We carried out a survey of infrared star clusters and stellar groups on the 2MASS J, H and Ks all-sky release Atlas in the Northern and Equatorial Milky Way (350deg {$<$} l {$<$} 360 deg, 0deg {$<$} l {$<$} 230 deg). The search in this zone complements that in the Southern Milky Way (Dutra et al. \textbackslash cite\{Dutra03\}a). The method concentrates efforts on the directions of known optical and radio nebulae. The present study provides 167 new infrared clusters, stellar groups and candidates. Combining the two studies for the whole Milky Way, 346 infrared clusters, stellar groups and candidates were discovered, whereas 315 objects were previously known. They constitute an important new sample for future detailed studies.}, keywords = {Astrophysics,Galaxy: open clusters and associations: general,infrared: general}, annotation = {ADS Bibcode: 2003A\&A...404..223B}}
@article{bica_updated_2020, title = {An {{Updated SMC}} and {{Magellanic Bridge Catalog}} of {{Star Clusters}}, {{Associations}} and {{Related Objects}}}, author = {Bica, Eduardo and Westera, Pieter and Kerber, Leandro de O. and Dias, Bruno and Maia, Francisco and Santos Jr., Jo{\~a}o F. C. and Barbuy, Beatriz and Oliveira, Raphael A. P.}, year = {2020}, month = jan, journal = {arXiv:1907.08642 [astro-ph]}, eprint = {1907.08642}, primaryclass = {astro-ph}, urldate = {2020-01-10}, abstract = {We present a catalog of star clusters, associations and related extended objects in the Small Magellanic Cloud and the Magellanic Bridge with 2741 entries, a factor 2 more than a previous version from a decade ago. Literature data till December 2018 are included. The identification of star clusters was carried out with digital atlases in various bands currently available in DSS and MAMA imaging surveys. In particular, we cross-identified recent cluster samples from the VMC, OGLE-IV and SMASH surveys, confirming new clusters and pointing out equivalencies. A major contribution of the present catalog consists in the accurate central positions for clusters and small associations, including a new sample of 45 clusters or candidates in the SMC and 19 in the Bridge, as well as a compilation of the most reliable age and metallicity values from the literature. A general catalog must also deal with the recent discoveries of 27 faint and ultra-faint star clusters and galaxies projected on the far surroundings of the Clouds, most of them from the DES survey. The information on these objects has been complemented with photometric, spectroscopic and kinematical follow-up data from the literature. The underluminous galaxies around the Magellanic System, still very few as compared to the predictions from \$\textbackslash Lambda\$ Cold Dark Matter simulations, can bring constraints to galaxy formation and hierarchical evolution. Furthermore, we provide diagnostics, when possible, of the nature of the ultra-faint clusters, searching for borders of the Magellanic System extensions into the Milky Way gravitational potential.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@book{binney_galactic_1987, title = {Galactic Dynamics}, author = {Binney, James and Tremaine, Scott}, year = {1987}}
@article{blundell_weight_2015, title = {Weight {{Uncertainty}} in {{Neural Networks}}}, author = {Blundell, Charles and Cornebise, Julien and Kavukcuoglu, Koray and Wierstra, Daan}, year = {2015}, month = may, journal = {arXiv e-prints}, volume = {arXiv:1505.05424}, doi = {10.48550/arXiv.1505.05424}, urldate = {2022-12-19}, abstract = {We introduce a new, efficient, principled and backpropagation-compatible algorithm for learning a probability distribution on the weights of a neural network, called Bayes by Backprop. It regularises the weights by minimising a compression cost, known as the variational free energy or the expected lower bound on the marginal likelihood. We show that this principled kind of regularisation yields comparable performance to dropout on MNIST classification. We then demonstrate how the learnt uncertainty in the weights can be used to improve generalisation in non-linear regression problems, and how this weight uncertainty can be used to drive the exploration-exploitation trade-off in reinforcement learning.}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@book{boffin_ecology_2015, title = {Ecology of {{Blue Straggler Stars}}}, author = {Boffin, Henri M. J. and Carraro, Giovanni and Beccari, Giacomo}, year = {2015}, month = jan, series = {Astrophysics and {{Space Science Library}}}, volume = {413}, publisher = {{Springer Berlin, Heidelberg}}, keywords = {Astrophysics - Solar and Stellar Astrophysics,Physics}}
@misc{bonanno_origin_2022, title = {On the Origin of the Dichotomy of Stellar Activity Cycles}, author = {Bonanno, Alfio and Corsaro, Enrico}, year = {2022}, month = oct, number = {arXiv:2210.11305}, eprint = {2210.11305}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2210.11305}, urldate = {2022-10-21}, abstract = {The presence of possible correlations between stellar rotation rate \$\textbackslash Omega\$ and the frequency of the activity cycle \$\textbackslash omega\_\textbackslash mathrm\{cyc\}\$ is still much debated. We implement a new Bayesian classification algorithm based on a simultaneous regression analysis of multiple scaling laws and we demonstrate the existence of two different scalings in the \$\textbackslash log\_\{10\} \textbackslash omega\_\textbackslash mathrm\{cyc\}\$ -- \$\textbackslash log\_\{10\} \textbackslash Omega\$ plane for an extended Mt.\textasciitilde Wilson sample of 67 stars. Thanks to metallicity measurements obtained from both ESA Gaia and high-resolution spectroscopy, we argue that the origin of this dichotomy is likely related to the chemical composition: stars whose magnetic cycle frequency increases with rotation rate are less metallic than stars whose magnetic cycle frequency decreases with stellar rotation rates. On the contrary, no clear difference in chromospheric magnetic activity indicators characterizes the two branches.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Solar and Stellar Astrophysics}}
@article{bonatto_mapping_2013, title = {Mapping the Differential Reddening in Globular Clusters}, author = {Bonatto, Charles and Campos, Fab{\'i}ola and Oliveira, Kepler S.}, year = {2013}, month = oct, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {435}, number = {1}, eprint = {1307.3935}, pages = {263--272}, issn = {1365-2966, 0035-8711}, doi = {10.1093/mnras/stt1304}, urldate = {2019-10-18}, abstract = {We build differential-reddening maps for 66 Galactic globular clusters (GCs) with archival HST WFC/ACS F606W and F814W photometry. Because of the different GC sizes (characterised by the half-light radius \$R\_h\$) and distances to the Sun, the WFC/ACS field of view (\$200\textbackslash arcsec\textbackslash times200\textbackslash arcsec\$) coverage (\$R\_\{obs\}\$) lies in the range \$1\textbackslash la R\_\{obs\}/R\_h\textbackslash la15\$ for about 85\% of the sample, with about 10\% covering only the inner (\$R\_\{obs\}\textbackslash la R\_h\$) parts. We divide the WFC/ACS field of view across each cluster in a regular cell grid, and extract the stellar-density Hess diagram from each cell, shifting it in colour and magnitude along the reddening vector until matching the mean diagram. Thus, the maps correspond to the internal dispersion of the reddening around the mean. Depending on the number of available stars (i.e. probable members with adequate photometric errors), the angular resolution of the maps range from \$\textbackslash approx7\textbackslash arcsec\textbackslash times7\textbackslash arcsec\$ to \$\textbackslash approx20\textbackslash arcsec\textbackslash times20\textbackslash arcsec\$. We detect spatially-variable extinction in the 66 globular clusters studied, with mean values ranging from \$\textbackslash mEBV\textbackslash approx0.018\$ (NGC\textbackslash,6981) up to \$\textbackslash mEBV\textbackslash approx0.16\$ (Palomar\textbackslash,2). Differential-reddening correction decreases the observed foreground reddening and the apparent distance modulus but, since they are related to the same value of \textbackslash EBV, the distance to the Sun is conserved. Fits to the mean-ridge lines of the highly-extincted and photometrically scattered globular cluster Palomar\textbackslash,2 show that age and metallicity also remain unchanged after the differential-reddening correction, but measurement uncertainties decrease because of the reduced scatter. The lack of systematic variations of \textbackslash mEBV\textbackslash{} with both the foreground reddening and the sampled cluster area indicates that the main source of differential reddening is interstellar.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\22VVL7XI\\1307.html}}
@article{bonilla-barroso_gravity_2022, title = {Gravity or Turbulence {{V}}: {{Star}} Forming Regions Undergoing Violent Relaxation}, shorttitle = {Gravity or Turbulence {{V}}}, author = {{Bonilla-Barroso}, Andrea and {Ballesteros-Paredes}, J. and Hern{\'a}ndez, Jesus and Aguilar, Luis and Zamora, Manuel and Hartmann, Lee W. and Kuznetsova, Aleksandra and Camacho, Vianey and Lora, Ver{\'o}nica}, year = {2022}, month = jan, journal = {arXiv:2201.11286 [astro-ph]}, eprint = {2201.11286}, primaryclass = {astro-ph}, urldate = {2022-02-01}, abstract = {Using numerical simulations of the formation and evolution of stellar clusters within molecular clouds, we show that the stars in clusters formed within collapsing molecular cloud clumps exhibit a constant velocity dispersion regardless of their mass, as expected in a violent relaxation processes. In contrast, clusters formed in turbulence-dominated environments exhibit an \{\textbackslash it inverse\} mass segregated velocity dispersion, where massive stars exhibit larger velocity dispersions than low-mass cores, consistent with massive stars formed in massive clumps, which in turn, are formed through strong shocks. We furthermore use Gaia EDR3 to show that the stars in the Orion Nebula Cluster exhibit a constant velocity dispersion as a function of mass, suggesting that it has been formed by collapse within one free-fall time of its parental cloud, rather than in a turbulence-dominated environment during many free-fall times of a supported cloud. Additionally, we have addressed several of the criticisms of models of collapsing star forming regions: namely, the age spread of the ONC, the comparison of the ages of the stars to the free-fall time of the gas that formed it, the star formation efficiency, and the mass densities of clouds vs the mass densities of stellar clusters, showing that observational and numerical data are consistent with clusters forming in clouds undergoing a process of global, hierarchical and chaotic collapse, rather than been supported by turbulence.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SJQQALHH\\2201.html}}
@article{borissova_new_2018, title = {New {{Galactic}} Star Clusters Discovered in the Disc Area of the {{VVVX}} Survey}, author = {Borissova, J. and Ivanov, V. D. and Lucas, P. W. and Kurtev, R. and {Alonso-Garcia}, J. and Ram{\'i}rez Alegr{\'i}a, S. and Minniti, D. and Froebrich, D. and Hempel, M. and Medina, N. and Chen{\'e}, A.-N. and Kuhn, M. A.}, year = {2018}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {481}, number = {3}, pages = {3902}, doi = {10.1093/mnras/sty2354}, urldate = {2019-09-03}, abstract = {The `VISTA Variables in the V\'ia L\'actea eXtended (VVVX)' ESO Public Survey is a near-infrared photometric sky survey that covers nearly 1700 deg\textsuperscript{2} towards the Galactic disc and bulge. It is well-suited to search for new open clusters, hidden behind dust and gas. The pipeline processed and calibrated K\textsubscript{S}-band tile images of 40 per cent of the disc area covered by VVVX was visually inspected for stellar overdensities. Then, we identified cluster candidates by examination of the composite JHK\textsubscript{S} colour images. The colour-magnitude diagrams of the cluster candidates are constructed. Whenever possible the Gaia DR2 parameters are used to calculate the mean proper motions, radial velocities, reddening and distances. We report the discovery of 120 new infrared clusters and stellar groups. Approximately half of them (47 per cent) are faint, compact, highly reddened, and they seem to be associated with other indicators of recent star formation, such as nearby Young Stellar Objects, Masers, H II regions or bubbles. The preliminary distance determinations allow us to trace the clusters up to 4.5 kpc, but most of the cluster candidates are centred at 2.2 kpc. The mean proper motions of the clusters show that in general they follow the disc motion of the Galaxy.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\9IWQWRVD\\Borissova et al. - 2018 - New Galactic star clusters discovered in the disc .pdf;C\:\\Users\\Emily\\Zotero\\storage\\K9LSEWCE\\abstract.html}}
@article{borissova_small_2020, title = {Small Scale Star Formation as Revealed by {{VVVX}} Galactic Cluster Candidates}, author = {Borissova, J. and Kurtev, R. and Amarinho, N. and {Alonso-Garcia}, J. and Alegria, S. Ramirez and Bernal, S. and Medina, N. and Chene, A.-N. and Ivanov, V. D. and Lucas, P. W. and Minniti, D.}, year = {2020}, month = oct, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2009.14372}, pages = {staa3045}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa3045}, urldate = {2020-10-07}, abstract = {We report a search and analysis of obscured cluster candidates in the "VISTA Variables in the Via Lactea eXtended (VVVX)" ESO Public Survey area encompassing the region between 229.4 {$<$} l {$<$} 295.2 and -4.3 {$<$} b {$<$} 4.4 of the southern Galactic disk. We discover and propose 88 new clusters. We improve the completeness of the embedded cluster population in this region, adding small size (linear diameters of 0.2-1.4 pc) and relatively far objects (heliocentric distance between 2 and 4 kpc) to existing catalogues. Nine candidates are proposed to be older open cluster candidates. Three of them (VVVX CL204, 207, 208) have sufficient numbers of well-resolved stellar members to allow us to determine some basic cluster parameters. We confirm their nature as older, low-mass open clusters. Photometric analysis of 15 known clusters shows that they have ages above 20Myr, and masses below 2000Msun: in general, their proper motions follow the motion of the disk. We outline some groups of clusters, most probably formed within the same dust complex. Broadly, our candidates follow the network of filamentary structure in the remaining dust. Thus, in this part of the southern disk of the Galaxy, we have found recent star formation, producing small size and young clusters, in addition to the well known, massive young clusters, including NGC3603, Westerlund2 and the Carina Nebula Complex.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HXVXCHYL\\2009.html}}
@article{bossini_age_2019, title = {Age Determination for 269 {{Gaia DR2}} Open Clusters}, author = {Bossini, D. and Vallenari, A. and Bragaglia, A. and {Cantat-Gaudin}, T. and Sordo, R. and {Balaguer-N{\'u}{\~n}ez}, L. and Jordi, C. and Moitinho, A. and Soubiran, C. and Casamiquela, L. and Carrera, R. and Heiter, U.}, year = {2019}, month = mar, journal = {Astronomy \& Astrophysics}, volume = {623}, pages = {A108}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201834693}, urldate = {2019-09-05}, abstract = {\emph{Context{$<$}i/{$>$}. The \emph{Gaia{$<$}i/{$>$} Second Data Release provides precise astrometry and photometry for more than 1.3 billion sources. This catalog opens a new era concerning the characterization of open clusters and test stellar models, paving the way for better understanding of the disk properties.\emph{Aims{$<$}i/{$>$}. The aim of the paper is to improve the knowledge of cluster parameters, using only the unprecedented quality of the \emph{Gaia{$<$}i/{$>$} photometry and astrometry.\emph{Methods{$<$}i/{$>$}. We have made use of the membership determination based on the precise \emph{Gaia{$<$}i/{$>$} astrometry and photometry. We applied an automated Bayesian tool, BASE-9, to fit stellar isochrones on the observed \emph{G{$<$}i/{$>$}, \emph{G{$<$}i/{$>$}\textsubscript{BP{$<$}sub/{$>$}, \emph{G{$<$}i/{$>$}\textsubscript{RP{$<$}sub/{$>$} magnitudes of the high probability member stars.\emph{Results{$<$}i/{$>$}. We derive parameters such as age, distance modulus, and extinction for a sample of 269 open clusters, selecting only low reddening objects and discarding very young clusters, for which techniques other than isochrone-fitting are more suitable for estimating ages.}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2019}, langid = {english}}
@article{boubert_completeness_2020, title = {Completeness of the {{Gaia-verse II}}: What Are the Odds That a Star Is Missing from {{Gaia DR2}}?}, shorttitle = {Completeness of the {{Gaia-verse II}}}, author = {Boubert, Douglas and Everall, Andrew}, year = {2020}, month = may, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {497}, number = {4}, pages = {4246--4261}, urldate = {2020-05-20}, abstract = {The second data release of the Gaia mission contained astrometry and photometry for an incredible 1,692,919,135 sources, but how many sources did Gaia miss and where do they lie on the sky? The answer to this question will be crucial for any astronomer attempting to map the Milky Way with Gaia DR2. We infer the completeness of Gaia DR2 by exploiting the fact that it only contains sources with at least five astrometric detections. The odds that a source achieves those five detections depends on both the number of observations and the probability that an observation of that source results in a detection. We predict the number of times that each source was observed by Gaia and assume that the probability of detection is either a function of magnitude or a distribution as a function of magnitude. We fit both these models to the 1.7 billion stars of Gaia DR2, and thus are able to robustly predict the completeness of Gaia across the sky as a function of magnitude. We extend our selection function to account for crowding in dense regions of the sky, and show that this is vitally important, particularly in the Galactic bulge and the Large and Small Magellanic Clouds. We find that the magnitude limit at which Gaia is still 99\% complete varies over the sky from \$G=18.9\$ to \$21.3\$. We have created a new Python package selectionfunctions (https://github.com/gaiaverse/selectionfunctions) which provides easy access to our selection functions.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\V8H2SQXK\\2005.html}}
@article{boubert_completeness_2020-1, title = {Completeness of the {{Gaia-verse I}}: When and Where Were {{Gaia}}'s Eyes on the Sky during {{DR2}}?}, shorttitle = {Completeness of the {{Gaia-verse I}}}, author = {Boubert, Douglas and Everall, Andrew and Holl, Berry}, year = {2020}, month = apr, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {497}, number = {2}, pages = {1826--1841}, urldate = {2020-05-04}, abstract = {The Gaia space mission is crafting revolutionary astrometric, photometric and spectroscopic catalogues that will allow us to map our Galaxy, but only if we know the completeness of this Gaia-verse of catalogues: what stars does it contain and what stars is it missing? We argue that the completeness is driven by Gaia's spinning-and-precessing scanning law and will apply this principle to the Gaia-verse over this series. We take a first step by identifying the periods in time that did not contribute any measurements to Gaia DR2; these gaps create ribbons of incompleteness across the sky that will bias any study that ignores them, although some of these gaps may be filled in future data releases. Our first approach was to use the variable star photometry to identify the 94 gaps longer than 1\% of a day. Our second approach was to predict the number of observations of every point on the sky, which in comparison to the reported number of detections revealed additional gaps in the astrometry and spectroscopy. Making these predictions required us to make the most precise, publicly-available determination of the Gaia scanning law. Using this scanning law, we further identified that most stars fainter than \$G=22\$ in DR2 have spurious magnitudes due to a miscalibration resulting from a thunderstorm over Madrid. Our list of gaps and precision scanning law will allow astronomers to know when Gaia's eye was truly on their binary star, exoplanet or microlensing event during the time period of the second data release.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\KNBRGZF5\\2004.html}}
@article{bovy_extreme_2011, title = {Extreme Deconvolution: {{Inferring}} Complete Distribution Functions from Noisy, Heterogeneous and Incomplete Observations}, shorttitle = {Extreme Deconvolution}, author = {Bovy, Jo and Hogg, David W. and Roweis, Sam T.}, year = {2011}, month = jun, journal = {Annals of Applied Statistics}, volume = {5}, doi = {10.1214/10-AOAS439}, urldate = {2020-09-11}, abstract = {We generalize the well-known mixtures of Gaussians approach to density estimation and the accompanying Expectation-Maximization technique for finding the maximum likelihood parameters of the mixture to the case where each data point carries an individual d-dimensional uncertainty covariance and has unique missing data properties. This algorithm reconstructs the error-deconvolved or "underlying" distribution function common to all samples, even when the individual data points are samples from different distributions, obtained by convolving the underlying distribution with the heteroskedastic uncertainty distribution of the data point and projecting out the missing data directions. We show how this basic algorithm can be extended with conjugate priors on all of the model parameters and a "split-and-merge" procedure designed to avoid local maxima of the likelihood. We demonstrate the full method by applying it to the problem of inferring the three-dimensional velocity distribution of stars near the Sun from noisy two-dimensional, transverse velocity measurements from the Hipparcos satellite.}, keywords = {Bayesian inference,density estimation,Expectation-maximization,missing data,multivariate estimation,noise}}
@article{bovy_galpy_python_2015, title = {Galpy: {{A}} Python {{Library}} for {{Galactic Dynamics}}}, shorttitle = {Galpy}, author = {Bovy, Jo}, year = {2015}, month = feb, journal = {The Astrophysical Journal Supplement Series}, volume = {216}, pages = {29}, issn = {0067-0049}, doi = {10.1088/0067-0049/216/2/29}, urldate = {2023-04-26}, abstract = {I describe the design, implementation, and usage of galpy, a python package for galactic-dynamics calculations. At its core, galpy consists of a general framework for representing galactic potentials both in python and in C (for accelerated computations); galpy functions, objects, and methods can generally take arbitrary combinations of these as arguments. Numerical orbit integration is supported with a variety of Runge-Kutta-type and symplectic integrators. For planar orbits, integration of the phase-space volume is also possible. galpy supports the calculation of action-angle coordinates and orbital frequencies for a given phase-space point for general spherical potentials, using state-of-the-art numerical approximations for axisymmetric potentials, and making use of a recent general approximation for any static potential. A number of different distribution functions (DFs) are also included in the current release; currently, these consist of two-dimensional axisymmetric and non-axisymmetric disk DFs, a three-dimensional disk DF, and a DF framework for tidal streams. I provide several examples to illustrate the use of the code. I present a simple model for the Milky Way's gravitational potential consistent with the latest observations. I also numerically calculate the Oort functions for different tracer populations of stars and compare them to a new analytical approximation. Additionally, I characterize the response of a kinematically warm disk to an elliptical m = 2 perturbation in detail. Overall, galpy consists of about 54,000 lines, including 23,000 lines of code in the module, 11,000 lines of test code, and about 20,000 lines of documentation. The test suite covers 99.6\% of the code. galpy is available at http://github.com/jobovy/galpy with extensive documentation available at http://galpy.readthedocs.org/en/latest.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,galaxies: general,galaxies: kinematics and dynamics,Galaxy: fundamental parameters}, annotation = {ADS Bibcode: 2015ApJS..216...29B}}
@article{bravi_gaia-eso_2018, title = {The {{Gaia-ESO Survey}}: A Kinematical and Dynamical Study of Four Young Open Clusters}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Bravi, L. and Zari, E. and Sacco, G. G. and Randich, S. and Jeffries, R. D. and Jackson, R. J. and Franciosini, E. and Moraux, E. and {L{\'o}pez-Santiago}, J. and Pancino, E. and Spina, L. and Wright, N. J. and {Jim{\'e}nez-Esteban}, F. M. and Klutsch, A. and Roccatagliata, V. and Gilmore, G. and Bragaglia, A. and Flaccomio, E. and Francois, P. and Koposov, S. E. and Bayo, A. and Carraro, G. and Costado, M. T. and Damiani, F. and Frasca, A. and Hourihane, A. and Jofr{\'e}, P. and Lardo, C. and Lewis, J. and Magrini, L. and Morbidelli, L. and Prisinzano, L. and Sousa, S. G. and Worley, C. C. and Zaggia, S.}, year = {2018}, month = jul, journal = {Astronomy and Astrophysics}, volume = {615}, pages = {A37}, issn = {0004-6361}, doi = {10.1051/0004-6361/201832645}, urldate = {2022-03-24}, abstract = {Context. The origin and dynamical evolution of star clusters is an important topic in stellar astrophysics. Several models have been proposed in order to understand the formation of bound and unbound clusters and their evolution, and they can be tested by examining the kinematical and dynamical properties of clusters over a wide range of ages and masses. {$<$}BR /{$>$} Aims: We use the Gaia-ESO Survey products to study four open clusters (IC 2602, IC 2391, IC 4665, and NGC 2547) that lie in the age range between 20 and 50 Myr. {$<$}BR /{$>$} Methods: We employ the gravity index {$\gamma$} and the equivalent width of the lithium line at 6708 \AA{} together with effective temperature T\textsubscript{eff} and the metallicity of the stars in order to discard observed contaminant stars. Then we derive the cluster radial velocity dispersions {$\sigma$}\textsubscript{c}, the total cluster mass M\textsubscript{tot}, and the half mass radius r\textsubscript{hm}. Using the Gaia-DR1 TGAS catalogue, we independently derive the intrinsic velocity dispersion of the clusters from the astrometric parameters of cluster members. {$<$}BR /{$>$} Results: The intrinsic radial velocity dispersions derived by the spectroscopic data are higher than those derived from the TGAS data, possibly due to the different masses of the considered stars. Using M\textsubscript{tot} and r\textsubscript{hm} we derive the virial velocity dispersion {$\sigma$}\textsubscript{vir} and we find that three out of four clusters are supervirial. This result is in agreement with the hypothesis that these clusters are dispersing, as predicted by the "residual gas expulsion" scenario. However, recent simulations show that the virial ratio of young star clustersmay be overestimated if it is determined using the global velocity dispersion, since the clusters are not fully relaxed.}, langid = {english}}
@article{bressan_parsec_2012, title = {{{PARSEC}}: Stellar Tracks and Isochrones with the {{PAdova}} and {{TRieste Stellar Evolution Code}}}, shorttitle = {{{PARSEC}}}, author = {Bressan, Alessandro and Marigo, Paola and Girardi, {\relax L{\'e}o}. and Salasnich, Bernardo and Dal Cero, Claudia and Rubele, Stefano and Nanni, Ambra}, year = {2012}, month = nov, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {427}, pages = {127--145}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2012.21948.x}, urldate = {2020-06-24}, abstract = {We present the updated version of the code used to compute stellar evolutionary tracks in Padova. It is the result of a thorough revision of the major input physics, together with the inclusion of the pre-main sequence phase, not present in our previous releases of stellar models. Another innovative aspect is the possibility of promptly generating accurate opacity tables fully consistent with any selected initial chemical composition, by coupling the Opacity Project At Livermore (OPAL) data at high temperatures to the molecular opacities computed with our \ae SOPUS code. In this work, we present extended sets of stellar evolutionary models for various initial chemical compositions, while other sets with different metallicities and/or different distributions of heavy elements are being computed. For the present release of models, we adopt the solar distribution of heavy elements from the recent revision by Caffau et al., corresponding to a Sun's metallicity Z {$\simeq$} 0.0152. From all computed sets of stellar tracks, we also derive isochrones in several photometric systems. The aim is to provide the community with the basic tools to model star clusters and galaxies by means of population synthesis techniques.}, keywords = {Hertzsprung-Russell and colour magnitude diagrams,stars: evolution,stars: interiors,stars: low-mass}}
@article{bressert_spatial_2010, title = {The Spatial Distribution of Star Formation in the Solar Neighbourhood: Do All Stars Form in Dense Clusters?}, shorttitle = {The Spatial Distribution of Star Formation in the Solar Neighbourhood}, author = {Bressert, E. and Bastian, N. and Gutermuth, R. and Megeath, S. T. and Allen, L. and Evans, II, Neal J. and Rebull, L. M. and Hatchell, J. and Johnstone, D. and Bourke, T. L. and Cieza, L. A. and Harvey, P. M. and Merin, B. and Ray, T. P. and Tothill, N. F. H.}, year = {2010}, month = nov, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {409}, pages = {L54-L58}, issn = {0035-8711}, doi = {10.1111/j.1745-3933.2010.00946.x}, urldate = {2021-11-09}, abstract = {We present a global study of low-mass, young stellar object (YSO) surface densities ({$\Sigma$}) in nearby ({$<$}500pc) star-forming regions based on a comprehensive collection of Spitzer Space Telescope surveys. We show that the distribution of YSO surface densities in the solar neighbourhood is a smooth distribution, being adequately described by a lognormal function from a few to 103 YSOs pc-2, with a peak at \textasciitilde 22 stars pc-2 and a dispersion of . We do not find evidence for multiple discrete modes of star formation (e.g. clustered and distributed). Comparing the observed surface density distribution to previously reported surface density threshold definitions of clusters, we find that the fraction of stars in clusters is crucially dependent on the adopted definitions, ranging from 40 to 90 per cent. However, we find that only a low fraction ({$<$}26 per cent) of stars are formed in dense environments where their formation/evolution (along with their circumstellar discs and/or planets) may be affected by the close proximity of their low-mass neighbours.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Solar and Stellar Astrophysics,infrared: stars,open clusters and associations: general,stars: formation,stars: protostars}, annotation = {ADS Bibcode: 2010MNRAS.409L..54B}}
@article{breuval_milky_way_2020, title = {The {{Milky Way Cepheid Leavitt}} Law Based on {{Gaia DR2}} Parallaxes of Companion Stars and Host Open Cluster Populations}, author = {Breuval, Louise and Kervella, Pierre and Anderson, Richard I. and Riess, Adam G. and Arenou, Fr{\'e}d{\'e}ric and Trahin, Boris and M{\'e}rand, Antoine and Gallenne, Alexandre and Gieren, Wolfgang and Storm, Jesper and Bono, Giuseppe and Pietrzy{\'n}ski, Grzegorz and Nardetto, Nicolas and Javanmardi, Behnam and Hocd{\'e}, Vincent}, year = {2020}, month = sep, journal = {arXiv:2006.08763 [astro-ph]}, eprint = {2006.08763}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {Classical Cepheids provide the foundation for the empirical extragalactic distance ladder. Milky Way Cepheids are the only stars in this class accessible to trigonometric parallax measurements. However, the parallaxes of Cepheids from the second Gaia data release (GDR2) are affected by systematics because of the absence of chromaticity correction, and occasionally by saturation. As a proxy for the parallaxes of 36 Galactic Cepheids, we adopt either the GDR2 parallaxes of their spatially resolved companions or the GDR2 parallax of their host open cluster. This novel approach allows us to bypass the systematics on the GDR2 Cepheids parallaxes that is induced by saturation and variability. We adopt a GDR2 parallax zero-point (ZP) of -0.046 mas with an uncertainty of 0.015 mas that covers most of the recent estimates. We present new Galactic calibrations of the Leavitt law in the V, J, H, K\_S , and Wesenheit W\_H bands. We compare our results with previous calibrations based on non-Gaia measurements and compute a revised value for the Hubble constant anchored to Milky Way Cepheids. From an initial Hubble constant of 76.18 +/- 2.37 km/s/Mpc based on parallax measurements without Gaia, we derive a revised value by adopting companion and average cluster parallaxes in place of direct Cepheid parallaxes, and we find H\_0 = 72.8 +/- 1.9 (statistical + systematics) +/- 1.9 (ZP) km/s/Mpc when all Cepheids are considered and H0 = 73.0 +/- 1.9 (statistical + systematics) +/- 1.9 (ZP) km/s/Mpc for fundamental mode pulsators only.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RXBAVTCG\\2006.html}}
@article{brown_gaia_2018, title = {Gaia {{Data Release}} 2 - {{Summary}} of the Contents and Survey Properties}, author = {Brown, A. G. A. and Vallenari, A. and Prusti, T. and de Bruijne, J. H. J. and Babusiaux, C. and {Bailer-Jones}, C. a. L. and Biermann, M. and Evans, D. W. and Eyer, L. and Jansen, F. and Jordi, C. and Klioner, S. A. and Lammers, U. and Lindegren, L. and Luri, X. and Mignard, F. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and van Leeuwen, F. and Walton, N. A. and Arenou, F. and Bastian, U. and Cropper, M. and Drimmel, R. and Katz, D. and Lattanzi, M. G. and Bakker, J. and Cacciari, C. and Casta{\~n}eda, J. and Chaoul, L. and Cheek, N. and Angeli, F. De and Fabricius, C. and Guerra, R. and Holl, B. and Masana, E. and Messineo, R. and Mowlavi, N. and Nienartowicz, K. and Panuzzo, P. and Portell, J. and Riello, M. and Seabroke, G. M. and Tanga, P. and Th{\'e}venin, F. and {Gracia-Abril}, G. and Comoretto, G. and {Garcia-Reinaldos}, M. and Teyssier, D. and Altmann, M. and Andrae, R. and Audard, M. and {Bellas-Velidis}, I. and Benson, K. and Berthier, J. and Blomme, R. and Burgess, P. and Busso, G. and Carry, B. and Cellino, A. and Clementini, G. and Clotet, M. and Creevey, O. and Davidson, M. and Ridder, J. De and Delchambre, L. and Dell'Oro, A. and Ducourant, C. and {Fern{\'a}ndez-Hern{\'a}ndez}, J. and Fouesneau, M. and Fr{\'e}mat, Y. and Galluccio, L. and {Garc{\'i}a-Torres}, M. and {Gonz{\'a}lez-N{\'u}{\~n}ez}, J. and {Gonz{\'a}lez-Vidal}, J. J. and Gosset, E. and Guy, L. P. and Halbwachs, J.-L. and Hambly, N. C. and Harrison, D. L. and Hern{\'a}ndez, J. and Hestroffer, D. and Hodgkin, S. T. and Hutton, A. and Jasniewicz, G. and {Jean-Antoine-Piccolo}, A. and Jordan, S. and Korn, A. J. and {Krone-Martins}, A. and Lanzafame, A. C. and Lebzelter, T. and L{\"o}ffler, W. and Manteiga, M. and Marrese, P. M. and {Mart{\'i}n-Fleitas}, J. M. and Moitinho, A. and Mora, A. and Muinonen, K. and Osinde, J. and Pancino, E. and Pauwels, T. and Petit, J.-M. and {Recio-Blanco}, A. and Richards, P. J. and Rimoldini, L. and Robin, A. C. and Sarro, L. M. and Siopis, C. and Smith, M. and Sozzetti, A. and S{\"u}veges, M. and Torra, J. and van Reeven, W. and Abbas, U. and Aramburu, A. Abreu and Accart, S. and Aerts, C. and Altavilla, G. and {\'A}lvarez, M. A. and Alvarez, R. and Alves, J. and Anderson, R. I. and Andrei, A. H. and Varela, E. Anglada and Antiche, E. and Antoja, T. and Arcay, B. and Astraatmadja, T. L. and Bach, N. and Baker, S. G. and {Balaguer-N{\'u}{\~n}ez}, L. and Balm, P. and Barache, C. and Barata, C. and Barbato, D. and Barblan, F. and Barklem, P. S. and Barrado, D. and Barros, M. and Barstow, M. A. and Mu{\~n}oz, S. Bartholom{\'e} and Bassilana, J.-L. and Becciani, U. and Bellazzini, M. and Berihuete, A. and Bertone, S. and Bianchi, L. and Bienaym{\'e}, O. and {Blanco-Cuaresma}, S. and Boch, T. and Boeche, C. and Bombrun, A. and Borrachero, R. and Bossini, D. and Bouquillon, S. and Bourda, G. and Bragaglia, A. and Bramante, L. and Breddels, M. A. and Bressan, A. and Brouillet, N. and Br{\"u}semeister, T. and Brugaletta, E. and Bucciarelli, B. and Burlacu, A. and Busonero, D. and Butkevich, A. G. and Buzzi, R. and Caffau, E. and Cancelliere, R. and Cannizzaro, G. and {Cantat-Gaudin}, T. and Carballo, R. and Carlucci, T. and Carrasco, J. M. and Casamiquela, L. and Castellani, M. and {Castro-Ginard}, A. and Charlot, P. and Chemin, L. and Chiavassa, A. and Cocozza, G. and Costigan, G. and Cowell, S. and Crifo, F. and Crosta, M. and Crowley, C. and Cuypers{\textdagger}, J. and Dafonte, C. and Damerdji, Y. and Dapergolas, A. and David, P. and David, M. and de Laverny, P. and Luise, F. De and March, R. De and de Martino, D. and de Souza, R. and de Torres, A. and Debosscher, J. and del Pozo, E. and Delbo, M. and Delgado, A. and Delgado, H. E. and Matteo, P. Di and Diakite, S. and Diener, C. and Distefano, E. and Dolding, C. and Drazinos, P. and Dur{\'a}n, J. and Edvardsson, B. and Enke, H. and Eriksson, K. and Esquej, P. and Bontemps, G. Eynard and Fabre, C. and Fabrizio, M. and Faigler, S. and Falc{\~a}o, A. J. and Casas, M. Farr{\`a}s and Federici, L. and Fedorets, G. and Fernique, P. and Figueras, F. and Filippi, F. and Findeisen, K. and Fonti, A. and Fraile, E. and Fraser, M. and Fr{\'e}zouls, B. and Gai, M. and Galleti, S. and Garabato, D. and {Garc{\'i}a-Sedano}, F. and Garofalo, A. and Garralda, N. and Gavel, A. and Gavras, P. and Gerssen, J. and Geyer, R. and Giacobbe, P. and Gilmore, G. and Girona, S. and Giuffrida, G. and Glass, F. and Gomes, M. and Granvik, M. and Gueguen, A. and Guerrier, A. and Guiraud, J. and {Guti{\'e}rrez-S{\'a}nchez}, R. and Haigron, R. and Hatzidimitriou, D. and Hauser, M. and Haywood, M. and Heiter, U. and Helmi, A. and Heu, J. and Hilger, T. and Hobbs, D. and Hofmann, W. and Holland, G. and Huckle, H. E. and Hypki, A. and Icardi, V. and Jan{\ss}en, K. and de Fombelle, G. Jevardat and Jonker, P. G. and Juh{\'a}sz, {\'A} L. and Julbe, F. and Karampelas, A. and Kewley, A. and Klar, J. and Kochoska, A. and Kohley, R. and Kolenberg, K. and Kontizas, M. and Kontizas, E. and Koposov, S. E. and Kordopatis, G. and {Kostrzewa-Rutkowska}, Z. and Koubsky, P. and Lambert, S. and Lanza, A. F. and Lasne, Y. and Lavigne, J.-B. and Fustec, Y. Le and {Poncin-Lafitte}, C. Le and Lebreton, Y. and Leccia, S. and Leclerc, N. and {Lecoeur-Taibi}, I. and Lenhardt, H. and Leroux, F. and Liao, S. and Licata, E. and Lindstr{\o}m, H. E. P. and Lister, T. A. and Livanou, E. and Lobel, A. and L{\'o}pez, M. and Managau, S. and Mann, R. G. and Mantelet, G. and Marchal, O. and Marchant, J. M. and Marconi, M. and Marinoni, S. and Marschalk{\'o}, G. and Marshall, D. J. and Martino, M. and Marton, G. and Mary, N. and Massari, D. and Matijevi{\v c}, G. and Mazeh, T. and McMillan, P. J. and Messina, S. and Michalik, D. and Millar, N. R. and Molina, D. and Molinaro, R. and Moln{\'a}r, L. and Montegriffo, P. and Mor, R. and Morbidelli, R. and Morel, T. and Morris, D. and Mulone, A. F. and Muraveva, T. and Musella, I. and Nelemans, G. and Nicastro, L. and Noval, L. and O'Mullane, W. and Ord{\'e}novic, C. and {Ord{\'o}{\~n}ez-Blanco}, D. and Osborne, P. and Pagani, C. and Pagano, I. and Pailler, F. and Palacin, H. and Palaversa, L. and Panahi, A. and Pawlak, M. and Piersimoni, A. M. and Pineau, F.-X. and Plachy, E. and Plum, G. and Poggio, E. and Poujoulet, E. and Pr{\v s}a, A. and Pulone, L. and Racero, E. and Ragaini, S. and Rambaux, N. and {Ramos-Lerate}, M. and Regibo, S. and Reyl{\'e}, C. and Riclet, F. and Ripepi, V. and Riva, A. and Rivard, A. and Rixon, G. and Roegiers, T. and Roelens, M. and {Romero-G{\'o}mez}, M. and Rowell, N. and Royer, F. and {Ruiz-Dern}, L. and Sadowski, G. and Sell{\'e}s, T. Sagrist{\`a} and Sahlmann, J. and Salgado, J. and Salguero, E. and Sanna, N. and {Santana-Ros}, T. and Sarasso, M. and Savietto, H. and Schultheis, M. and Sciacca, E. and Segol, M. and Segovia, J. C. and S{\'e}gransan, D. and Shih, I.-C. and Siltala, L. and Silva, A. F. and Smart, R. L. and Smith, K. W. and Solano, E. and Solitro, F. and Sordo, R. and Nieto, S. Soria and Souchay, J. and Spagna, A. and Spoto, F. and Stampa, U. and Steele, I. A. and Steidelm{\"u}ller, H. and Stephenson, C. A. and Stoev, H. and Suess, F. F. and Surdej, J. and Szabados, L. and {Szegedi-Elek}, E. and Tapiador, D. and Taris, F. and Tauran, G. and Taylor, M. B. and Teixeira, R. and Terrett, D. and Teyssandier, P. and Thuillot, W. and Titarenko, A. and Clotet, F. Torra and Turon, C. and Ulla, A. and Utrilla, E. and Uzzi, S. and Vaillant, M. and Valentini, G. and Valette, V. and van Elteren, A. and Hemelryck, E. Van and van Leeuwen, M. and Vaschetto, M. and Vecchiato, A. and Veljanoski, J. and Viala, Y. and Vicente, D. and Vogt, S. and von Essen, C. and Voss, H. and Votruba, V. and Voutsinas, S. and Walmsley, G. and Weiler, M. and Wertz, O. and Wevers, T. and Wyrzykowski, {\L} and Yoldas, A. and {\v Z}erjal, M. and Ziaeepour, H. and Zorec, J. and Zschocke, S. and Zucker, S. and Zurbach, C. and Zwitter, T.}, year = {2018}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {616}, pages = {A1}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201833051}, urldate = {2019-09-05}, abstract = {\emph{Context.{$<$}i/{$>$} We present the second \emph{Gaia{$<$}i/{$>$} data release, \emph{Gaia{$<$}i/{$>$} DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system.\emph{Aims.{$<$}i/{$>$} A summary of the contents of \emph{Gaia{$<$}i/{$>$} DR2 is presented, accompanied by a discussion on the differences with respect to \emph{Gaia{$<$}i/{$>$} DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of \emph{Gaia{$<$}i/{$>$} DR2 results.\emph{Methods.{$<$}i/{$>$} The raw data collected with the \emph{Gaia{$<$}i/{$>$} instruments during the first 22 months of the mission have been processed by the \emph{Gaia{$<$}i/{$>$} Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to \emph{Gaia{$<$}i/{$>$} DR1 in terms of completeness, performance, and richness of the data products. \emph{Results. Gaia{$<$}i/{$>$} DR2 contains celestial positions and the apparent brightness in \emph{G{$<$}i/{$>$} for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0.5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the \emph{G{$<$}i/{$>$}\textsubscript{BP{$<$}sub/{$>$} (330\textendash 680 nm) and \emph{G{$<$}i/{$>$}\textsubscript{RP{$<$}sub/{$>$} (630\textendash 1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally, \emph{Gaia{$<$}i/{$>$} DR2 also represents a new materialisation of the celestial reference frame in the optical, the \emph{Gaia{$<$}i/{$>$}-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to \emph{Gaia{$<$}i/{$>$} DR1, and we stress the need to consider the two data releases as independent. \emph{Conclusions. Gaia{$<$}i/{$>$} DR2 represents a major achievement for the \emph{Gaia{$<$}i/{$>$} mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the \emph{Gaia{$<$}i/{$>$} survey which covers a very substantial fraction of the volume of our galaxy.}}}}}}}}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, keywords = {Gaia Usage Guide,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SNC5TCDL\\Brown et al_2018_Gaia Data Release 2 - Summary of the contents and survey properties.pdf;C\:\\Users\\Emily\\Zotero\\storage\\IJG4WGM6\\aa33051-18.html}}
@article{brown_testing_2022, title = {Testing {{Feedback}} from {{Star Clusters}} in {{Simulations}} of the {{Milky Way Formation}}}, author = {Brown, Gillen and Gnedin, Oleg Y.}, year = {2022}, month = mar, journal = {arXiv:2203.00559 [astro-ph]}, eprint = {2203.00559}, primaryclass = {astro-ph}, urldate = {2022-03-03}, abstract = {We present a suite of galaxy formation simulations that directly model star cluster formation and disruption. Starting from a model previously developed by our group, here we introduce several improvements to the prescriptions for cluster formation and feedback, then test these updates using a large suite of cosmological simulations of Milky Way mass galaxies. We perform a differential analysis with the goal of understanding how each of the updates affects star cluster populations. Two key parameters are the momentum boost of supernova feedback \$f\_\{\textbackslash mathrm\{boost\}\}\$ and star formation efficiency per freefall time \$\textbackslash epsilon\_\{\textbackslash mathrm\{ff\}\}\$. We find that \$f\_\{\textbackslash mathrm\{boost\}\}\$ has a strong influence on the galactic star formation rate, with higher values leading to less star formation. The efficiency \$\textbackslash epsilon\_\{\textbackslash mathrm\{ff\}\}\$ does not have a significant impact on the global star formation rate, but dramatically changes cluster properties, with increasing \$\textbackslash epsilon\_\{\textbackslash mathrm\{ff\}\}\$ leading to a higher maximum cluster mass, shorter age spread of stars within clusters, and higher integrated star formation efficiencies. We also explore the redshift evolution of the observable cluster mass function, finding that most massive clusters have formed at high redshift \$z{$>$}4\$. Extrapolation of cluster disruption to \$z=0\$ produces good agreement with both the Galactic globular cluster mass function and age-metallicity relation. Our results emphasize the importance of using small-scale properties of galaxies to calibrate subgrid models of star cluster formation and feedback.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YJCSMVR9\\2203.html}}
@article{cadelano_radial_2020, title = {Radial Variation of the Stellar Mass Functions in the Globular Clusters {{M15}} and {{M30}}: Clues of a Non-Standard {{IMF}}?}, shorttitle = {Radial Variation of the Stellar Mass Functions in the Globular Clusters {{M15}} and {{M30}}}, author = {Cadelano, Mario and Dalessandro, Emanuele and Webb, Jeremy J. and Vesperini, Enrico and Lattanzio, Daniele and Beccari, Giacomo and Gomez, Matias and Monaco, Lorenzo}, year = {2020}, month = sep, journal = {arXiv:2009.02333 [astro-ph]}, eprint = {2009.02333}, primaryclass = {astro-ph}, urldate = {2020-09-10}, abstract = {We exploit a combination of high-resolution Hubble Space Telescope and wide-field ESO-VLT observations to study the slope of the global mass function (alphaG) and its radial variation (alpha(r)) in the two dense, massive and post core-collapse globular clusters M15 and M30. The available data-set samples the clusters' Main Sequence down to 0.2 Msun and the photometric completeness allows the study of the mass function between 0.40 Msun and 0.75 Msun from the central regions out to their tidal radii. We find that both clusters show a very similar variation in alpha(r) as a function of clustercentric distance. They both exhibit a very steep variation in alpha(r) in the central regions, which then attains almost constant values in the outskirts. Such a behavior can be interpreted as the result of long-term dynamical evolution of the systems driven by mass-segregation and mass-loss processes. We compare these results with a set of direct N-body simulations and find that they are only able to reproduce the observed values of alpha(r) and alphaG at dynamical ages (t/trh) significantly larger than those derived from the observed properties of both clusters. We investigate possible physical mechanisms responsible for such a discrepancy and argue that both clusters might be born with a non-standard (flatter/bottom-lighter) initial mass function.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\9FNZW2T3\\2009.html}}
@article{camargo_ngc1605a_2021, title = {{{NGC1605a}} and b: An Old Binary Open Cluster in the {{Galaxy}}}, shorttitle = {{{NGC1605a}} and b}, author = {Camargo, Denilso}, year = {2021}, month = sep, journal = {arXiv:2109.14664 [astro-ph]}, eprint = {2109.14664}, primaryclass = {astro-ph}, urldate = {2021-10-01}, abstract = {This work communicates the discovery of a binary open cluster within the Galaxy. NGC 1605 presents an unusual morphology with a sparse stellar distribution and a double core in close angular proximity. The 2MASS and Gaia-EDR3 field-star decontaminated colour-magnitude diagrams (CMDs) show two distinct stellar populations located at the same heliocentric distance of \$\textbackslash sim2.6\$ kpc suggesting that there are two clusters in the region, NGC 1605a and NGC 1605b, with ages of \$2\$ Gyr and \$600\$ Myr, respectively. Both Gaia parallax and PM distributions are compact and very similar indicating that they are open clusters (OCs) and share the same kinematics. The large age difference, 1.4 Gyr, points to a formation by tidal capture during a close encounter and the close spatial proximity and similar kinematics suggest an ongoing merger event. There are some prominent tidal debris that appear to trace the clusters' orbits during the close encounter and, unexpectedly, some of them appear to be bound structures, which may suggest that additionaly to the evaporation the merging clusters are being broken apart into smaller structures by the combination of Galactic disk, Perseus arm, and mutual tidal interactions. In this sense, the newly found binary cluster may be a key object on the observational validation of theoretical studies on binary cluster pairs formation by tidal capture as well as in the formation of massive clusters by merging, and tidal disruption of stellar systems.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6HSFHBV6\\2109.html}}
@article{cameron_estimation_2011, title = {On the {{Estimation}} of {{Confidence Intervals}} for {{Binomial Population Proportions}} in {{Astronomy}}: {{The Simplicity}} and {{Superiority}} of the {{Bayesian Approach}}}, shorttitle = {On the {{Estimation}} of {{Confidence Intervals}} for {{Binomial Population Proportions}} in {{Astronomy}}}, author = {Cameron, Ewan}, year = {2011}, month = jun, journal = {Publications of the Astronomical Society of Australia}, volume = {28}, pages = {128--139}, doi = {10.1071/AS10046}, urldate = {2020-09-02}, abstract = {I present a critical review of techniques for estimating confidence intervals on binomial population proportions inferred from success counts in small to intermediate samples. Population proportions arise frequently as quantities of interest in astronomical research; for instance, in studies aiming to constrain the bar fraction, active galactic nucleus fraction, supermassive black hole fraction, merger fraction, or red sequence fraction from counts of galaxies exhibiting distinct morphological features or stellar populations. However, two of the most widely-used techniques for estimating binomial confidence intervals - the `normal approximation' and the Clopper \& Pearson approach - are liable to misrepresent the degree of statistical uncertainty present under sampling conditions routinely encountered in astronomical surveys, leading to an ineffective use of the experimental data (and, worse, an inefficient use of the resources expended in obtaining that data). Hence, I provide here an overview of the fundamentals of binomial statistics with two principal aims: (i) to reveal the ease with which (Bayesian) binomial confidence intervals with more satisfactory behaviour may be estimated from the quantiles of the beta distribution using modern mathematical software packages (e.g. r, matlab, mathematica, idl, python); and (ii) to demonstrate convincingly the major flaws of both the `normal approximation' and the Clopper \& Pearson approach for error estimation.}, keywords = {methods: data analysis,methods: statistical}}
@article{cantat-gaudin_characterising_2018, title = {Characterising Open Clusters in the Solar Neighbourhood with the {{Tycho-Gaia Astrometric Solution}}}, author = {{Cantat-Gaudin}, T. and Vallenari, A. and Sordo, R. and Pensabene, F. and {Krone-Martins}, A. and Moitinho, A. and Jordi, C. and Casamiquela, L. and {Balaguer-N{\'u}nez}, L. and Soubiran, C. and Brouillet, N.}, year = {2018}, month = jul, journal = {Astronomy \& Astrophysics}, volume = {615}, pages = {A49}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201731251}, urldate = {2020-02-19}, abstract = {\emph{Context.{$<$}i/{$>$} The \emph{Tycho{$<$}i/{$>$}-\emph{Gaia{$<$}i/{$>$} Astrometric Solution (TGAS) subset of the first \emph{Gaia{$<$}i/{$>$} catalogue contains an unprecedented sample of proper motions and parallaxes for two million stars brighter than \emph{G{$<$}i/{$>$} \textasciitilde{} 12 mag.\emph{Aims.{$<$}i/{$>$} We take advantage of the full astrometric solution available for those stars to identify the members of known open clusters and compute mean cluster parameters using either TGAS or the fourth U.S. Naval Observatory CCD Astrograph Catalog (UCAC4) proper motions, and TGAS parallaxes.\emph{Methods.{$<$}i/{$>$} We apply an unsupervised membership assignment procedure to select high probability cluster members, we use a Bayesian/Markov Chain Monte Carlo technique to fit stellar isochrones to the observed 2MASS \emph{JHK{$<$}i/{$>$}\textsubscript{\emph{S{$<$}i/{$><$}sub/{$>$} magnitudes of the member stars and derive cluster parameters (age, metallicity, extinction, distance modulus), and we combine TGAS data with spectroscopic radial velocities to compute full Galactic orbits.\emph{Results.{$<$}i/{$>$} We obtain mean astrometric parameters (proper motions and parallaxes) for 128 clusters closer than about 2 kpc, and cluster parameters from isochrone fitting for 26 of them located within a distance of 1 kpc from the Sun. We show the orbital parameters obtained from integrating 36 orbits in a Galactic potential.}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\85NSI34G\\aa31251-17.html}}
@article{cantat-gaudin_characterizing_2021, title = {Characterizing and Correcting the Proper Motion Bias of the Bright {{Gaia EDR3}} Sources}, author = {{Cantat-Gaudin}, Tristan and Brandt, Timothy D.}, year = {2021}, month = mar, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2103.07432}, pages = {A124}, urldate = {2021-03-15}, abstract = {In this paper we characterize magnitude-dependent systematics in the proper motions of the Gaia EDR3 catalog and provide a prescription for their removal. The reference frame of bright stars (G{$<$}13) in EDR3 is known to rotate with respect to extragalactic objects, but this rotation has proven difficult to characterize and correct. We employ a sample of binary stars and a sample of open cluster members to characterize this proper motion bias as a magnitude-dependent spin of the reference frame. We show that the bias varies with G magnitude, reaching up to 80 \{\textbackslash mu\}as/yr for sources in the range G = 11 - 13, several times the formal EDR3 proper motion uncertainties. We also show evidence for an additional dependence on the color of the source, with a magnitude up to 10 \{\textbackslash mu\}as/yr. However, a color correction proportional to the effective wavenumber is unsatisfactory for very red or very blue stars and we do not recommend its use. We provide a recipe for a magnitude-dependent correction to align the proper motion of the Gaia EDR3 sources brighter than G=13 with the International Celestial Reference Frame.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6NZ72NZR\\2103.html}}
@article{cantat-gaudin_clusters_2020, title = {Clusters and Mirages: Cataloguing Stellar Aggregates in the {{Milky Way}}}, shorttitle = {Clusters and Mirages}, author = {{Cantat-Gaudin}, T. and Anders, F.}, year = {2020}, month = jan, journal = {Astronomy and Astrophysics}, volume = {633}, pages = {A99}, issn = {0004-6361}, doi = {10.1051/0004-6361/201936691}, urldate = {2020-06-24}, abstract = {Context. Many of the open clusters listed in modern catalogues were initially reported by visual astronomers as apparent overdensities of bright stars. As observational techniques and analysis methods continue to improve, some of them have been shown to be chance alignments of stars and not true clusters. Recent publications making use of Gaia DR2 data have provided membership lists for over a thousand clusters, however, many nearby objects listed in the literature have so far evaded detection. Aims: We aim to update the Gaia DR2 cluster census by performing membership determinations for known clusters that had been missed by previous studies and for recently-discovered clusters. We investigate a sub-set of non-detected clusters that, according to their literature parameters, should be easily visible in Gaia. Confirming or disproving the existence of old, inner-disc, high-altitude clusters is especially important as their survival or disruption is linked to the dynamical processes that drive the evolution of the Milky Way. Methods: We employed the Gaia DR2 catalogue and a membership assignment procedure, as well as visual inspections of spatial, proper motion, and parallax distributions. We used membership lists provided by other authors when available. Results: We derived membership lists for 150 objects, including ten that were already known prior to Gaia. We compiled a final list of members for 1481 clusters. Among the objects that we are still unable to identify with the Gaia data, we argue that many (mostly putatively old, relatively nearby, high-altitude objects) are not true clusters. Conclusions: At present, the only confirmed cluster located further than 500 pc away from the Galactic plane within the Solar circle is NGC 6791. It is likely that the objects discussed in this study only represent a fraction of the non-physical groupings erroneously listed in the catalogues as genuine open clusters and that those lists need further cleaning. Full Table 1 and the list of individual members are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/633/A99}, keywords = {Galaxy: stellar content,open clusters and associations: general}, file = {/home/ehunt/Zotero/storage/XYGPKEAY/Cantat-Gaudin_Anders_2019_Clusters and mirages_annotated.pdf}}
@article{cantat-gaudin_empirical_model_2023, title = {An Empirical Model of the {{Gaia DR3}} Selection Function}, author = {{Cantat-Gaudin}, Tristan and Fouesneau, Morgan and Rix, Hans-Walter and Brown, Anthony G. A. and {Castro-Ginard}, Alfred and {Kostrzewa-Rutkowska}, Zuzanna and Drimmel, Ronald and Hogg, David W. and Casey, Andrew R. and Khanna, Shourya and Oh, Semyeong and {Price-Whelan}, Adrian M. and Belokurov, Vasily and Saydjari, Andrew K. and Green, G.}, year = {2023}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {669}, pages = {A55}, doi = {10.1051/0004-6361/202244784}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,catalogs,methods: data analysis,methods: statistical}}
@article{cantat-gaudin_gaia_2018, title = {A {{Gaia DR2}} View of the Open Cluster Population in the {{Milky Way}}}, author = {{Cantat-Gaudin}, T. and Jordi, C. and Vallenari, A. and Bragaglia, A. and {Balaguer-N{\'u}{\~n}ez}, L. and Soubiran, C. and Bossini, D. and Moitinho, A. and {Castro-Ginard}, A. and {Krone-Martins}, A. and Casamiquela, L. and Sordo, R. and Carrera, R.}, year = {2018}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {618}, pages = {A93}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201833476}, urldate = {2019-09-03}, abstract = {\emph{Context.{$<$}i/{$>$} Open clusters are convenient probes of the structure and history of the Galactic disk. They are also fundamental to stellar evolution studies. The second \emph{Gaia{$<$}i/{$>$} data release contains precise astrometry at the submilliarcsecond level and homogeneous photometry at the mmag level, that can be used to characterise a large number of clusters over the entire sky.\emph{Aims.{$<$}i/{$>$} In this study we aim to establish a list of members and derive mean parameters, in particular distances, for as many clusters as possible, making use of \emph{Gaia{$<$}i/{$>$} data alone.\emph{Methods.{$<$}i/{$>$} We compiled a list of thousands of known or putative clusters from the literature. We then applied an unsupervised membership assignment code, UPMASK, to the \emph{Gaia{$<$}i/{$>$} DR2 data contained within the fields of those clusters.\emph{Results.{$<$}i/{$>$} We obtained a list of members and cluster parameters for 1229 clusters. As expected, the youngest clusters are seen to be tightly distributed near the Galactic plane and to trace the spiral arms of the Milky Way, while older objects are more uniformly distributed, deviate further from the plane, and tend to be located at larger Galactocentric distances. Thanks to the quality of \emph{Gaia{$<$}i/{$>$} DR2 astrometry, the fully homogeneous parameters derived in this study are the most precise to date. Furthermore, we report on the serendipitous discovery of 60 new open clusters in the fields analysed during this study.}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, keywords = {OC Analysis,OC Finder,Read}}
@article{cantat-gaudin_gaia_2019, title = {Gaia {{DR2}} Unravels Incompleteness of Nearby Cluster Population: New Open Clusters in the Direction of {{Perseus}}}, shorttitle = {Gaia {{DR2}} Unravels Incompleteness of Nearby Cluster Population}, author = {{Cantat-Gaudin}, T. and {Krone-Martins}, A. and Sedaghat, N. and Farahi, A. and de Souza, R. S. and Skalidis, R. and Malz, A. I. and Mac{\^e}do, S. and Moews, B. and Jordi, C. and Moitinho, A. and {Castro-Ginard}, A. and Ishida, E. E. O. and Heneka, C. and Boucaud, A. and Trindade, A. M. M.}, year = {2019}, month = apr, journal = {Astronomy \& Astrophysics}, volume = {624}, pages = {A126}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201834453}, urldate = {2019-09-06}, abstract = {\emph{Context.{$<$}i/{$>$} Open clusters (OCs) are popular tracers of the structure and evolutionary history of the Galactic disc. The OC population is often considered to be complete within 1.8 kpc of the Sun. The recent \emph{Gaia{$<$}i/{$>$} Data Release 2 (DR2) allows the latter claim to be challenged.\emph{Aims.{$<$}i/{$>$} We perform a systematic search for new OCs in the direction of Perseus using precise and accurate astrometry from \emph{Gaia{$<$}i/{$>$} DR2.\emph{Methods.{$<$}i/{$>$} We implemented a coarse-to-fine search method. First, we exploited spatial proximity using a fast density-aware partitioning of the sky via a \emph{k{$<$}i/{$>$}-d tree in the spatial domain of Galactic coordinates, (\emph{l{$<$}i/{$>$}, \emph{b{$<$}i/{$>$}). Secondly, we employed a Gaussian mixture model in the proper motion space to tag fields quickly around OC candidates. Thirdly, we applied an unsupervised membership assignment method, UPMASK, to scrutinise the candidates. We visually inspected colour-magnitude diagrams to validate the detected objects. Finally, we performed a diagnostic to quantify the significance of each identified over-density in proper motion and in parallax space.\emph{Results.{$<$}i/{$>$} We report the discovery of 41 new stellar clusters. This represents an increment of at least 20\% of the previously known OC population in this volume of the Milky Way. We also report on the clear identification of NGC 886, an object previously considered an asterism. This study challenges the previous claim of a near-complete sample of OCs up to 1.8 kpc. Our results reveal that this claim requires revision, and a complete census of nearby OCs is yet to be found.}}}}}}}}}}, copyright = {\textcopyright{} ESO 2019}, langid = {english}, keywords = {OC Finder,Read}, file = {/home/ehunt/Zotero/storage/PC7M8PJB/Cantat-Gaudin et al_2019_Gaia DR2 unravels incompleteness of nearby cluster population_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\PC7M8PJB\\Cantat-Gaudin et al_2019_Gaia DR2 unravels incompleteness of nearby cluster population.pdf;C\:\\Users\\Emily\\Zotero\\storage\\2CLYRLC2\\aa34453-18.html}}
@article{cantat-gaudin_milky_2022, title = {Milky {{Way Star Clusters}} and {{Gaia}}: {{A Review}} of the {{Ongoing Revolution}}}, shorttitle = {Milky {{Way Star Clusters}} and {{Gaia}}}, author = {{Cantat-Gaudin}, Tristan}, year = {2022}, month = feb, journal = {Universe}, volume = {8}, pages = {111}, doi = {10.3390/universe8020111}, urldate = {2022-03-25}, abstract = {The unprecedented quality of the astrometric measurements obtained with the ESA Gaia spacecraft have initiated a revolution in Milky Way astronomy. Studies of star clusters in particular have been transformed by the precise proper motions and parallaxes measured by Gaia over the entire sky as well as Gaia's deep all-sky photometry. This paper presents an overview of the many topics of cluster science that have been impacted by the Gaia DR1, DR2, and EDR3 catalogues from their release to the end of the year 2021. These topics include the identification of known clusters and the discovery of new objects, the formation of young clusters and associations, and the long-term evolution of clusters and their stellar content. In addition to the abundance of scientific results, Gaia is changing the way astronomers work with high-volume and high-dimensionality datasets and is teaching us precious lessons to deal with its upcoming data releases and with the large-scale astronomical surveys of the future.}}
@article{cantat-gaudin_painting_2020, title = {Painting a Portrait of the {{Galactic}} Disc with Its Stellar Clusters}, author = {{Cantat-Gaudin}, T. and Anders, F. and {Castro-Ginard}, A. and Jordi, C. and {Romero-G{\'o}mez}, M. and Soubiran, C. and Casamiquela, L. and Tarricq, Y. and Moitinho, A. and Vallenari, A. and Bragaglia, A. and {Krone-Martins}, A. and Kounkel, M.}, year = {2020}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {640}, pages = {A1}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202038192}, urldate = {2020-08-13}, abstract = {Methods. We relied on a set of objects with well-determined parameters in the literature to train an artificial neural network to estimate parameters from the Gaia photometry of cluster members and their mean parallax. Results. We obtain reliable parameters for 1867 clusters. Our catalogue confirms the relative lack of old stellar clusters in the inner disc (with a few notable exceptions). We also quantify and discuss the variation of scale height with cluster age, and we detect the Galactic warp in the distribution of old clusters. Conclusions. This work results in a large and homogeneous cluster catalogue, allowing one to trace the structure of the disc out to distances of {$\sim$}4 kpc. However, the present sample is still unable to trace the outer spiral arm of the Milky Way, which indicates that the outer disc cluster census might still be incomplete.}, langid = {english}, file = {/home/emily/Zotero/storage/M7GXH393/Cantat-Gaudin et al_2020_Painting a portrait of the Galactic disc with its stellar clusters_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\M7GXH393\\Cantat-Gaudin et al_2020_Painting a portrait of the Galactic disc with its stellar clusters.pdf}}
@article{cardelli_relationship_1989, title = {The Relationship between Infrared, Optical, and Ultraviolet Extinction}, author = {Cardelli, Jason A. and Clayton, Geoffrey C. and Mathis, John S.}, year = {1989}, month = oct, journal = {The Astrophysical Journal}, volume = {345}, pages = {245--256}, issn = {0004-637X}, doi = {10.1086/167900}, urldate = {2019-12-06}, abstract = {The parameterized extinction data of Fitzpatrick and Massa (1986, 1988) for the ultraviolet and various sources for the optical and near-infrared are used to derive a meaningful average extinction law over the 3.5 micron to 0.125 wavelength range which is applicable to both diffuse and dense regions of the interstellar medium. The law depends on only one parameter R(V) = A(V)/E(B-V). An analytic formula is given for the mean extinction law which can be used to calculate color excesses or to deredden observations. The validity of the law over a large wavelength interval suggests that the processes which modify the sizes and compositions of grains are stochastic in nature and very efficient.}, keywords = {CCM,Computational Astrophysics,dust,extinction,Infrared Spectra,Interstellar Extinction,Interstellar Matter,Iue,read,Ultraviolet Spectra,Visible Spectrum}}
@article{carrera_one_2022, title = {One {{Star}} to {{Tag Them All}} ({{OSTTA}}): {{I}}. {{Radial}} Velocities and Chemical Abundances for 20 Poorly Studied Open Clusters}, shorttitle = {One {{Star}} to {{Tag Them All}} ({{OSTTA}})}, author = {Carrera, R. and Casamiquela, L. and Bragaglia, A. and Carretta, E. and {Carbajo-Hijarrubia}, J. and Jordi, C. and {Alonso-Santiago}, J. and {Balaguer-Nu{\~n}ez}, L. and Baratella, M. and D'Orazi, V. and Lucatello, S. and Soubiran, C.}, year = {2022}, month = apr, journal = {arXiv:2204.03765 [astro-ph]}, eprint = {2204.03765}, primaryclass = {astro-ph}, urldate = {2022-04-19}, abstract = {Context: Open clusters are ideal laboratories to investigate a variety of astrophysical topics, from the properties of the Galactic disc to stellar evolution models. For this purpose, we need to know their chemical composition in detail. Unfortunately, the number of systems with chemical abundances determined from high resolution spectroscopy remains small. Aims: Our aim is to increase the number of open clusters with radial velocities and chemical abundances determined from high resolution spectroscopy by sampling a few stars in clusters not studied previously. Methods: We obtained high resolution spectra with the FIES spectrograph at NOT for 41 stars belonging to 20 open clusters. These stars have high astrometric membership probabilities, determined from the Gaia second data release. Results: We derived radial velocities for all the observed stars, which were used to confirm their membership to the corresponding clusters. For Gulliver\textbackslash,37 we cannot be sure the observed star is a real member. We derived atmospheric parameters for the 32 stars considered real cluster members. We discarded five stars because they have very low gravity or atmospheric parameters were not properly constrained due to low signal-to-noise ratio spectra. Therefore, detailed chemical abundances were determined for 28 stars belonging to 17 clusters. For most of them, this is the first chemical analysis available in the literature. Finally, we compared the clusters in our sample to a large population of well studied clusters. The studied systems follow the trends, both chemical and kinematical, described by the majority of open clusters. Worth noticing that the three most metal-poor studied clusters (NGC\textbackslash,1027, NGC\textbackslash,1750 and Trumpler 2) are enhanced in Si but not in the other alpha-elements studied (Mg, Ca and Ti).}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{casado_discovery_2023, title = {Discovery and Description of Two Young Open Clusters in the Primordial Group of {{NGC}} 6871}, author = {Casado, Juan and Hendy, Yasser}, year = {2023}, month = jan, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2211.12843}, primaryclass = {astro-ph}, pages = {stad071}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stad071}, urldate = {2023-02-28}, abstract = {A primordial group of open clusters containing NGC 6871 is confirmed and described through Gaia DR3 data and the previous literature. It is a star-forming complex containing at least six young OCs, including Teutsch 8, FSR 198 and Biurakan 2. Two nearby OCs (Casado 82 and Casado-Hendy 1) are newly identified and studied in detail and found to be also members of the cited group. The parameters of the components are sufficiently similar to postulate the case of at least six clusters born from a single GMC. None of the cluster pairs of the group seems to be an authentic binary cluster, with the possible exception of the candidate pair Teutsch 8/FSR 198. Instead, NGC 6871 seems to be disintegrating, and the primordial group members appear to be dispersing out rapidly. Searching for new open clusters in the vicinity of young or grouped OCs using Gaia data is an efficient strategy to find new associated OCs forming primordial groups.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{casado_new_2021, title = {New {{Open Clusters Found}} by {{Manual Mining}} of {{Data}} in {{Gaia DR2}}}, author = {Casado, Juan}, year = {2021}, journal = {Research in Astronomy and Astrophysics}, volume = {21}, number = {5}, pages = {117}, urldate = {2020-09-14}, abstract = {The physical nature of a series of 20 new open clusters is confirmed employing existing data on putative star members, mainly from second Gaia Data Release (DR2). The clusters were discovered as overdensities of stars by visual inspection of either photographic DSS plates or proper motion plots of random source fields. The reported objects are not present in the most comprehensive or recent catalogs of stellar clusters and associations. For all of them, clumps of comoving stars are revealed in the proper motion space. The parallaxes of the clumped stars are compatible with the real existence of open clusters over narrow ranges of distances. Surface density calculations, free of most noise from non-member sources, allow in some cases differentiating a cluster core and an extended cluster corona. Color-magnitude diagrams generally show a definite main sequence that allows the confirmation of the physical existence of the clusters and some of their characteristics. Two of the new clusters seem to form a double system with a common origin. Several of the new clusters challenge the claim of near completeness of the known OC population in the distance range from 1.0 to 1.8 kpc of the Sun (Kharchenko et al. 2013).}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TV67NWSS\\2009.html}}
@article{casagrande_hamiltonian-based_2012, title = {Hamiltonian-{{Based Clustering}}: {{Algorithms}} for {{Static}} and {{Dynamic Clustering}} in {{Data Mining}} and {{Image Processing}}}, shorttitle = {Hamiltonian-{{Based Clustering}}}, author = {Casagrande, D. and Sassano, M. and Astolfi, A.}, year = {2012}, month = aug, journal = {IEEE Control Systems Magazine}, volume = {32}, number = {4}, pages = {74--91}, issn = {1066-033X}, doi = {10.1109/MCS.2012.2196321}, abstract = {The large amount of data available for analysis and management raises the need for defining, determining, and extracting meaningful information from the data. Hence in scientific, engineering, and economics studies, the practice of clustering data arises naturally when sets of data have to be divided into subgroups with the aim of possibly deducting common features for data belonging to the same subgroup. For instance, the innovation scoreboard [1] (see Figure 1) allows for the classification of the countries into four main clusters corresponding to the level of innovation defining the ``leaders,'' the ``followers,'' the ``trailing,'' and the ``catching up'' countries. Many other disciplines may require or take advantage of a clustering of data, from market research [2] to gene expression analysis [3], from biology to image processing [4][7]. Therefore, several clustering techniques have been developed (for details see ``Review of Clustering Algorithms'').}, keywords = {Clustering Algorithm}, file = {C\:\\Users\\Emily\\Zotero\\storage\\XLH2WP38\\Casagrande et al. - 2012 - Hamiltonian-Based Clustering Algorithms for Stati.pdf;C\:\\Users\\Emily\\Zotero\\storage\\KRAITSG6\\6244703.html}}
@article{casali_stellar_2020, title = {Stellar {{Population Astrophysics}} ({{SPA}}) with {{TNG}}. {{The}} Old Open Clusters {{Collinder}} 350, {{Gulliver}} 51, {{NGC}} 7044, and {{Ruprecht}} 171}, author = {Casali, G. and Magrini, L. and Frasca, A. and Bragaglia, A. and Catanzaro, G. and D'Orazi, V. and Sordo, R. and Carretta, E. and Origlia, L. and Andreuzzi, G. and Fu, X. and Vallenari, A.}, year = {2020}, month = sep, journal = {arXiv:2009.06695 [astro-ph]}, eprint = {2009.06695}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {In the framework of the Stellar Population Astrophysics (SPA) project, we present new observations and spectral analysis of four sparsely studied open clusters, namely Collinder 350, Gulliver 51, NGC 7044, and Ruprecht 171. We exploit the HARPS-N spectrograph at the TNG telescope to acquire high-resolution optical spectra for 15 member stars of four clusters. We derive stellar parameters using both the EW analysis and the spectral fitting technique. We compute elemental abundances for light, a-, iron-peak, and n-capture elements using the EW measurement approach. We investigate the origin of the correlation between metallicity and stellar parameters derived with the EW method for the coolest stars of the sample (Teff {$<$} 4300 K). The correlation is likely due to the challenging continuum setting and to a general inaccuracy of model atmospheres used to reproduce the conditions of very cool giant stars. We locate the properties of our clusters in the radial distributions of metallicity and abundance ratios, comparing our results with clusters from the Gaia-ESO and APOGEE surveys. We present the [X/Fe]-[Fe/H] and [X/Fe]-Rgc trends for elements in common between the two surveys and derive the C and Li abundances as a function of the evolutionary phase and compare them with theoretical models. The SPA survey allows us to fully characterise the chemistry of nearby clusters. With a single set of spectra, we provide chemical abundances for some chemical elements, which are comparable to those obtained in two of the largest surveys combined. The metallicities and abundance ratios of our clusters fit very well in the radial distributions defined by the recent literature, reinforcing the importance of star clusters to outline the spatial distribution of abundances in our Galaxy. Moreover, the abundances of C and Li agree with evolutionary prescriptions for their masses and metallicities.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Z8ES2X8A\\2009.html}}
@article{casamiquela_abundance-age_2021, title = {Abundance-Age Relations with Red Clump Stars in Open Clusters}, author = {Casamiquela, L. and Soubiran, C. and Jofr{\'e}, P. and Chiappini, C. and Lagarde, N. and Tarricq, Y. and Carrera, R. and Jordi, C. and {Balaguer-N{\'u}{\~n}ez}, L. and {Carbajo-Hijarrubia}, J. and {Blanco-Cuaresma}, S.}, year = {2021}, month = mar, journal = {arXiv:2103.14692 [astro-ph]}, eprint = {2103.14692}, primaryclass = {astro-ph}, urldate = {2021-03-30}, abstract = {Context: Precise chemical abundances coupled with reliable ages are key ingredients to understand the chemical history of our Galaxy. Open Clusters (OCs) are useful for this purpose because they provide ages with good precision. Aims: The aim of this work is to investigate the relations of different chemical abundance ratios vs age traced by red clump (RC) stars in OCs. Methods: We analyze a large sample of 209 reliable members in 47 OCs with available high-resolution spectroscopy. We applied a differential line-by-line analysis to provide a comprehensive chemical study of 25 chemical species. This sample is among the largest samples of OCs homogeneously characterized in terms of atmospheric parameters, detailed chemistry, and ages. Results: In our metallicity range (-0.2{$<$}[M/H]{$<$}+0.2) we find that while most Fe-peak and alpha elements have flat dependence with age, the s-process elements show decreasing trends with increasing age with a remarkable knee at 1 Gyr. For Ba, Ce, Y, Mo and Zr we find a plateau at young ages ({$<$} 1 Gyr). We investigate the relations of all possible combinations among the computed chemical species with age. We find 19 combinations with significant slopes, including [Y/Mg] and [Y/Al]. The ratio [Ba/alpha] is the one with the most significant correlations found. Conclusions: We find that the [Y/Mg] relation found in the literature using Solar twins is compatible with the one found here in the Solar neighbourhood. The age-abundance relations show larger scatter for clusters at large distances (d{$>$}1 kpc) than for the Solar neighbourhood, particularly in the outer disk. We conclude that these relations need to be understood also in terms of the complexity of the chemical space introduced by the Galactic dynamics, on top of pure nucleosynthetic arguments, especially out of the local bubble.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{casamiquela_differential_2019, title = {Differential Abundances of Open Clusters and Their Tidal Tails: Chemical Tagging and Chemical Homogeneity}, shorttitle = {Differential Abundances of Open Clusters and Their Tidal Tails}, author = {Casamiquela, L. and Tarricq, Y. and Soubiran, C. and {Blanco-Cuaresma}, S. and Jofr{\'e}, P. and Heiter, U. and Maia, M. Tucci}, year = {2019}, month = dec, journal = {arXiv:1912.08539 [astro-ph]}, eprint = {1912.08539}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {Well studied Open Clusters (OCs) in the Solar neighbourhood are used as reference objects to test galactic and stellar theories. For that purpose their chemical composition needs to be known with a high level of confidence. The aims of this work are (1) to determine accurate and precise abundances of 22 chemical species (from Na to Eu) in the Hyades, Praesepe and Rupecht 147 using a large number of stars at different evolutionary states, (2) to evaluate the level of chemical homogeneity of these OCs, (3) to compare their chemical signatures. We gathered \$\textbackslash sim\$800 high resolution and high S/N spectra of \$\textbackslash sim\$100 members in the three OCs, obtained with the latest memberships based on Gaia DR2 data. We build a pipeline which computes atmospheric parameters and strictly line-by-line differential abundances among twin stars in our sample, which allows us to reach a very high precision in the abundances (0.01-0.02 dex in most of the elements). We find large differences in the absolute abundances in some elements, which can be attributed to diffusion, NLTE effects or systematics in the analysis. For the three OCs, we find strong correlations in the differential abundances between different pairs of elements, which can be explained by some level of chemical inhomogeneity. We compare differential abundances of several stars from the Hyades and Praesepe tails: the stars that differ more in chemical abundances also have distinct kinematics, even though they have been identified as members of the tail. With this technique we find that the Hyades and Preasepe have the same chemical signature when G dwarfs and K giants are considered. Despite a certain level of inhomogeneity in each cluster, it is still possible to clearly distinguish the chemical signature of the older cluster Ruprecht\textasciitilde 147 when compared to the others.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GSJNPQBB\\1912.html}}
@article{casamiquela_impossibility_2021, title = {The (Im)Possibility of Strong Chemical Tagging}, author = {Casamiquela, L. and {Castro-Ginard}, A. and Anders, F. and Soubiran, C.}, year = {2021}, month = aug, journal = {arXiv:2108.13431 [astro-ph]}, eprint = {2108.13431}, primaryclass = {astro-ph}, urldate = {2021-09-15}, abstract = {The possibility of identifying co-natal stars that have dispersed into the Galactic disc based on chemistry only is called strong chemical tagging. Its feasibility has been debated for a long time, with the promise of reconstructing the detailed star-formation history of a large fraction of stars in the Galactic disc. We investigate the feasibility of strong chemical tagging using known member stars of open clusters. We analysed the largest sample of cluster members that have been homogeneously characterised with high-resolution differential abundances for 16 different elements. We also investigated the possibility of finding the known clusters in the APOGEE DR16 red clump sample with 18 chemical species. For both purposes, we used a clustering algorithm and an unsupervised dimensionality reduction technique to blindly search for groups of stars in chemical space. Even if the internal coherence of the stellar abundances in the same cluster is high, typically 0.03 dex, the overlap in the chemical signatures of the clusters is large. In the sample with the highest precision and no field stars, we only recover 9 out of the 31 analysed clusters at a 40\% threshold of homogeneity and precision. This ratio slightly increases when we only use clusters with 7 or more members. In the APOGEE sample, field stars are present along with four populated clusters. In this case, only one of the open clusters was moderately recovered. In our best-case scenario, more than 70\% of the groups of stars are in fact statistical groups that contain stars belonging to different real clusters. This indicates that the chances of recovering the majority of birth clusters dissolved in the field are slim, even with the most advanced clustering techniques. We show that different stellar birth sites can have overlapping chemical signatures [abridged]}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6WL7Y6GI\\2108.html}}
@misc{castro-ginard_estimating_selection_2023, title = {Estimating the Selection Function of {{Gaia DR3}} Sub-Samples}, author = {{Castro-Ginard}, A. and Brown, A. G. A. and {Kostrzewa-Rutkowska}, Z. and {Cantat-Gaudin}, T. and Drimmel, R. and Oh, S. and Belokurov, V. and Casey, A. R. and Fouesneau, M. and Khanna, S. and {Price-Whelan}, A. M. and Rix, H. W.}, year = {2023}, eprint = {2303.17738}, primaryclass = {astro-ph.GA}, archiveprefix = {arxiv}}
@article{castro-ginard_hunting_2019, title = {Hunting for Open Clusters in {{Gaia DR2}}: The {{Galactic}} Anticentre}, shorttitle = {Hunting for Open Clusters in {{Gaia DR2}}}, author = {{Castro-Ginard}, A. and Jordi, C. and Luri, X. and {Cantat-Gaudin}, T. and {Balaguer-N{\'u}{\~n}ez}, L.}, year = {2019}, month = jul, journal = {Astronomy \& Astrophysics}, volume = {627}, number = {A35}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201935531}, urldate = {2019-09-03}, abstract = {\emph{Context{$<$}i/{$>$}. The \emph{Gaia{$<$}i/{$>$} Data Release 2 (DR2) provided an unprecedented volume of precise astrometric and excellent photometric data. In terms of data mining the \emph{Gaia{$<$}i/{$>$} catalogue, machine learning methods have shown to be a powerful tool, for instance in the search for unknown stellar structures. Particularly, supervised and unsupervised learning methods combined together significantly improves the detection rate of open clusters.\emph{Aims{$<$}i/{$>$}. We systematically scan \emph{Gaia{$<$}i/{$>$} DR2 in a region covering the Galactic anticentre and the Perseus arm (120\textdegree{} {$\leq$} \emph{l{$<$}i/{$>$} {$\leq$} 205\textdegree{} and -10\textdegree{} {$\leq$} \emph{b{$<$}i/{$>$} {$\leq$} 10\textdegree ), with the goal of finding any open clusters that may exist in this region, and fine tuning a previously proposed methodology and successfully applied to TGAS data, adapting it to different density regions.\emph{Methods{$<$}i/{$>$}. Our methodology uses an unsupervised, density-based, clustering algorithm, DBSCAN, that identifies overdensities in the five-dimensional astrometric parameter space (\emph{l{$<$}i/{$>$}, \emph{b{$<$}i/{$>$}, \emph{{$\varpi<$}i/{$>$}, \emph{{$\mu<$}i/{$>$}\textsubscript{\emph{{$\alpha<$}i/{$>$}\textsuperscript{*{$<$}sup/{$><$}sub/{$>$}, \emph{{$\mu<$}i/{$>$}\textsubscript{\emph{{$\delta<$}i/{$><$}sub/{$>$}) that may correspond to physical clusters. The overdensities are separated into physical clusters (open clusters) or random statistical clusters using an artificial neural network to recognise the isochrone pattern that open clusters show in a colour magnitude diagram.\emph{Results{$<$}i/{$>$}. The method is able to recover more than 75\% of the open clusters confirmed in the search area. Moreover, we detected 53 open clusters unknown previous to \emph{Gaia{$<$}i/{$>$} DR2, which represents an increase of more than 22\% with respect to the already catalogued clusters in this region.\emph{Conclusions{$<$}i/{$>$}. We find that the census of nearby open clusters is not complete. Different machine learning methodologies for a blind search of open clusters are complementary to each other; no single method is able to detect 100\% of the existing groups. Our methodology has shown to be a reliable tool for the automatic detection of open clusters, designed to be applied to the full \emph{Gaia{$<$}i/{$>$} DR2 catalogue.}}}}}}}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2019}, langid = {english}, keywords = {OC Finder,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\4DXGWEUR\\Castro-Ginard et al. - 2019 - Hunting for open clusters in Gaia DR2 the Galacti.pdf;C\:\\Users\\Emily\\Zotero\\storage\\7YCWBE58\\Castro-Ginard et al. - 2019 - Hunting for open clusters in Gaia DR2 the Galacti_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\IYRV576R\\aa35531-19.html}}
@article{castro-ginard_hunting_2020, title = {Hunting for Open Clusters in \textbackslash textit\{\vphantom\}{{Gaia}}\vphantom\{\} {{DR2}}: \$582\$ New {{OCs}} in the {{Galactic}} Disc}, shorttitle = {Hunting for Open Clusters in \textbackslash textit\{\vphantom\}{{Gaia}}\vphantom\{\} {{DR2}}}, author = {{Castro-Ginard}, A. and Jordi, C. and Luri, X. and {Cid-Fuentes}, J. {\'A}lvarez and Casamiquela, L. and Anders, F. and {Cantat-Gaudin}, T. and Mongui{\'o}, M. and {Balaguer-N{\'u}{\~n}ez}, L. and Sol{\`a}, S. and Badia, R. M.}, year = {2020}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {635}, number = {A45}, urldate = {2020-01-22}, abstract = {Open clusters are key targets for both Galaxy structure and evolution and stellar physics studies. Since \textbackslash textit\{Gaia\} DR2 publication, the discovery of undetected clusters has proven that our samples were not complete. Our aim is to exploit the Big Data capabilities of machine learning to detect new open clusters in \textbackslash textit\{Gaia\} DR2, and to complete the open cluster sample to enable further studies on the Galactic disc. We use a machine learning based methodology to systematically search in the Galactic disc, looking for overdensities in the astrometric space and identifying them as open clusters using photometric information. First, we use an unsupervised clustering algorithm, DBSCAN, to blindly search for these overdensities in \textbackslash textit\{Gaia\} DR2 \$(l,b,\textbackslash varpi,\textbackslash mu\_\{\textbackslash alpha\^*\},\textbackslash mu\_\textbackslash delta)\$. After that, we use a deep learning artificial neural network trained on colour-magnitude diagrams to identify isochrone patterns in these overdensities, and to confirm them as open clusters. We find \$582\$ new open clusters distributed along the Galactic disc, in the region \$|b| {$<$} 20\$. We can detect substructure in complex regions, and identify the tidal tails of a disrupting cluster UBC\textasciitilde\$274\$ of \$\textbackslash sim 3\$ Gyr located at \$\textbackslash sim 2\$ kpc. Adapting the methodology into a Big Data environment allows us to target the search driven by physical properties of the open clusters, instead of being driven by its computational requirements. This blind search for open clusters in the Galactic disc increases in a \$45\textbackslash\%\$ the number of known open clusters.}, keywords = {ACG,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,new open cluster,open cluster discoveries,read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YGC6V4HU\\2001.html}}
@article{castro-ginard_hunting_2022, title = {Hunting for Open Clusters in {{Gaia EDR3}}: \$664\$ New Open Clusters Found with {{OCfinder}}}, shorttitle = {Hunting for Open Clusters in {{Gaia EDR3}}}, author = {{Castro-Ginard}, A. and Jordi, C. and Luri, X. and {Cantat-Gaudin}, T. and Carrasco, J. M. and Casamiquela, L. and Anders, F. and {Balaguer-N{\'u}{\~n}ez}, L. and Badia, R. M.}, year = {2022}, journal = {Astronomy \& Astrophysics}, volume = {661}, eprint = {2111.01819}, pages = {A118}, urldate = {2021-11-04}, abstract = {The improvements in the precision of the published data in \textbackslash textit\{Gaia\} EDR3 with respect to \textbackslash textit\{Gaia\} DR2, particularly for parallaxes and proper motions, offer the opportunity to increase the number of known open clusters in the Milky Way by detecting farther and fainter objects that have so far go unnoticed. Our aim is to keep completing the open cluster census in the Milky Way with the detection of new stellar groups in the Galactic disc. We use \textbackslash textit\{Gaia\} EDR3 up to magnitude \$G = 18\$ mag, increasing in one unit the magnitude limit and therefore the search volume explored in our previous studies. We use the \textbackslash texttt\{OCfinder\} method to search for new open clusters in \textbackslash textit\{Gaia\} EDR3 using a Big Data environment. As a first step, \textbackslash texttt\{OCfinder\} identifies stellar statistical overdensities in the five dimensional astrometric space (position, parallax and proper motions) using the \textbackslash texttt\{DBSCAN\} clustering algorithm. Then, these overdensities are classified into random statistical overdensities or real physical open clusters using a deep artificial neural network trained on well-characterised \$G\$, \$G\_\{\textbackslash rm BP\} - G\_\{\textbackslash rm RP\}\$ colour-magnitude diagrams. We report the discovery of \$664\$ new open clusters within the Galactic disc, most of them located beyond \$1\$ kpc from the Sun. From the estimation of ages, distances and line-of-sight extinctions of these open clusters, we see that young clusters align following the Galactic spiral arms while older ones are dispersed in the Galactic disc. Furthermore, we find that most open clusters are located at low Galactic altitudes with the exception of a few groups older than \$1\$ Gyr. We show the success of the \textbackslash texttt\{OCfinder\} method leading to the discovery of a total of \$1\textbackslash,310\$ open clusters (joining the discoveries here with the previous ones based on \textbackslash textit\{Gaia\} DR2)[abridged]}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\VI2WX55X\\2111.html}}
@article{castro-ginard_milky_2021, title = {On the {{Milky Way}} Spiral Arms from Open Clusters in {{Gaia EDR3}}}, author = {{Castro-Ginard}, A. and McMillan, P. J. and Luri, X. and Jordi, C. and {Romero-G{\'o}mez}, M. and {Cantat-Gaudin}, T. and Casamiquela, L. and Tarricq, Y. and Soubiran, C. and Anders, F.}, year = {2021}, month = may, journal = {Astronomy \& Astrophysics}, volume = {652}, eprint = {2105.04590}, pages = {A162}, urldate = {2021-05-14}, abstract = {Context. The physical processes driving the formation of Galactic spiral arms are still under debate. Studies using open clusters favour the description of the Milky Way spiral arms as long-lived structures following the classical density wave theory. Current studies comparing the Gaia DR2 field stars kinematic information of the Solar neighbourhood to simulations, find a better agreement with short-lived arms with a transient behaviour. Aims. Our aim is to provide an observational, data-driven view of the Milky Way spiral structure and its dynamics using open clusters as the main tracers, and to contrast it with simulation-based approaches. We use the most complete catalogue of Milky Way open clusters, with astrometric Gaia EDR3 updated parameters, estimated astrophysical information and radial velocities, to re-visit the nature of the spiral pattern of the Galaxy. Methods. We use a Gaussian mixture model to detect overdensities of open clusters younger than 30 Myr that correspond to the Perseus, Local, Sagittarius and Scutum spiral arms, respectively. We use the birthplaces of the open cluster population younger than 80 Myr to trace the evolution of the different spiral arms and compute their pattern speed. We analyse the age distribution of the open clusters across the spiral arms to explore the differences in the rotational velocity of stars and spiral arms. Results. We are able to increase the range in Galactic azimuth where present-day spiral arms are described, better estimating its parameters by adding 264 young open clusters to the 84 high-mass star-forming regions used so far, thus increasing by a 314\% the number of tracers. We use the evolution of the open clusters from their birth positions to find that spiral arms nearly co-rotate with field stars at any given radius, discarding a common spiral pattern speed for the spiral arms explored. [abridged]}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\R2HJREKU\\2105.html}}
@article{castro-ginard_new_2018, title = {A New Method for Unveiling Open Clusters in {{Gaia}} - {{New}} Nearby Open Clusters Confirmed by {{DR2}}}, author = {{Castro-Ginard}, A. and Jordi, C. and Luri, X. and Julbe, F. and Morvan, M. and {Balaguer-N{\'u}{\~n}ez}, L. and {Cantat-Gaudin}, T.}, year = {2018}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {618}, pages = {A59}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201833390}, urldate = {2019-09-03}, abstract = {\emph{Context{$<$}i/{$>$}. The publication of the \emph{Gaia{$<$}i/{$>$} Data Release 2 (\emph{Gaia{$<$}i/{$>$} DR2) opens a new era in astronomy. It includes precise astrometric data (positions, proper motions, and parallaxes) for more than 1.3 billion sources, mostly stars. To analyse such a vast amount of new data, the use of data-mining techniques and machine-learning algorithms is mandatory.\emph{Aims{$<$}i/{$>$}. A great example of the application of such techniques and algorithms is the search for open clusters (OCs), groups of stars that were born and move together, located in the disc. Our aim is to develop a method to automatically explore the data space, requiring minimal manual intervention.\emph{Methods{$<$}i/{$>$}. We explore the performance of a density-based clustering algorithm, DBSCAN, to find clusters in the data together with a supervised learning method such as an artificial neural network (ANN) to automatically distinguish between real OCs and statistical clusters.\emph{Results{$<$}i/{$>$}. The development and implementation of this method in a five-dimensional space (\emph{l{$<$}i/{$>$}, \emph{b{$<$}i/{$>$}, \emph{{$\varpi<$}i/{$>$}, \emph{{$\mu<$}i/{$>$}\textsubscript{\emph{{$\alpha<$}i/{$>$}\textsuperscript{*{$<$}sup/{$><$}sub/{$>$}, \emph{{$\mu<$}i/{$>$}\textsubscript{\emph{{$\delta<$}i/{$><$}sub/{$>$}) with the Tycho-Gaia Astrometric Solution (TGAS) data, and a posterior validation using \emph{Gaia{$<$}i/{$>$} DR2 data, lead to the proposal of a set of new nearby OCs. \emph{Conclusions{$<$}i/{$>$}. We have developed a method to find OCs in astrometric data, designed to be applied to the full \emph{Gaia{$<$}i/{$>$} DR2 archive.}}}}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, keywords = {OC Finder,Read}}
@article{chan_deep-cee_2019, title = {Deep-{{CEE I}}: {{Fishing}} for {{Galaxy Clusters}} with {{Deep Neural Nets}}}, shorttitle = {Deep-{{CEE I}}}, author = {Chan, Matthew C. and Stott, John P.}, year = {2019}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {490}, number = {4}, eprint = {1906.08784}, pages = {5770--5787}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stz2936}, urldate = {2019-11-26}, abstract = {We introduce Deep-CEE (Deep Learning for Galaxy Cluster Extraction and Evaluation), a proof of concept for a novel deep learning technique, applied directly to wide-field colour imaging to search for galaxy clusters, without the need for photometric catalogues. This technique is complementary to traditional methods and could also be used in combination with them to confirm galaxy cluster candidates. We use a state-of-the-art probabilistic algorithm, adapted to localize and classify galaxy clusters from other astronomical objects in SDSS imaging. As there is an abundance of labelled data for galaxy clusters from previous classifications in publicly available catalogues, we do not need to rely on simulated data. This means we keep our training data as realistic as possible, which is advantageous when training a deep learning algorithm. Ultimately, we will apply our model to surveys such as LSST and Euclid to probe wider and deeper into unexplored regions of the Universe. This will produce large samples of both high redshift and low mass clusters, which can be utilized to constrain both environment-driven galaxy evolution and cosmology.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\T3SJ7U56\\1906.html}}
@article{chandrasekhar_stochastic_1943, title = {Stochastic {{Problems}} in {{Physics}} and {{Astronomy}}}, author = {Chandrasekhar, S}, year = {1943}, journal = {Reviews of Modern Physics}, volume = {15}, number = {1}, urldate = {2020-01-20}, keywords = {derivation,kth nearest neighbor,kth nearest neighbour,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2QAME7X3\\RevModPhys.15.pdf}}
@article{chattopadhyay_dynamical_2022, title = {Dynamical Double Black Holes and Their Host Cluster Properties}, author = {Chattopadhyay, Debatri and Hurley, Jarrod and Stevenson, Simon and Raidani, Arihant}, year = {2022}, month = feb, journal = {arXiv:2202.08924 [astro-ph, physics:gr-qc]}, eprint = {2202.08924}, primaryclass = {astro-ph, physics:gr-qc}, urldate = {2022-03-03}, abstract = {We investigate the relationship between the global properties of star clusters and their double black hole (DBH) populations. We use the code \{\textbackslash tt NBODY6\} to evolve a suite of star cluster models with an initial mass of \$\textbackslash mathcal\{O\}(10\^4)\$M\$\_\textbackslash odot\$ and varying initial parameters. We conclude that cluster metallicity plays the most significant role in determining the lifespan of a cluster, while the initial half-mass radius is dominant in setting the rate of BH exchange interactions in the central cluster regions. We find that the mass of interacting BHs, rather than how frequently their interactions with other BHs occur, is more crucial in the thermal expansion and eventual evaporation of the cluster. We formulate a novel approach to easily quantify the degree of BH-BH dynamical activity in each model. We report 12 in-cluster and three out-of-cluster (after ejection from the cluster) DBH mergers, of different types (inspiral, eccentric, hierarchical) across the ten \$N\$-body models presented. Our DBH merger efficiency is 3--4\$\textbackslash times10\^\{-5\}\$ mergers per M\$\_\textbackslash odot\$. We note the cluster initial density plays the most crucial role in determining the number of DBH mergers, with the potential presence of a transitional density point (between 1.2-3.8\$\textbackslash times10\^3\$M\$\_\textbackslash odot\$/pc\$\^3\$) below which the number of in-cluster mergers increases with cluster density and above which the increased stellar density acts to prevent in-cluster BH mergers. The importance of the history of dynamical interactions within the cluster in setting up the pathways to ejected DBH mergers is also discussed.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - High Energy Astrophysical Phenomena,General Relativity and Quantum Cosmology}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RG2MH28R\\2202.html}}
@article{chemel_search_2022, title = {Search for {{OB}} Associations in \{\textbackslash sl \vphantom\}{{Gaia}}\vphantom\{\} Early {{Data Release}} 3}, author = {Chemel, Alexander A. and {de Grijs}, Richard and Glushkova, Elena V. and Dambis, Andrey K.}, year = {2022}, month = jun, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2206.12935}, primaryclass = {astro-ph}, pages = {stac1780}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stac1780}, urldate = {2022-07-15}, abstract = {The distribution of young stars into OB associations has long been in need of updating. High-precision \{\textbackslash sl Gaia\} early Data Release 3 astrometry, coupled with modern machine-learning methods, allows this to be done. We have compiled a well-defined sample which includes OB stars and young open clusters, in total comprising about 47,700 objects. To break the sample down into groupings resembling associations, we applied the HDBSCAN\$\^\{*\}\$ clustering algorithm. We used a Monte Carlo method to estimate the kinematic ages of the resulting clusters and the Student's \$t\$-test to assess the significance of the linear correlations between proper motions and coordinates, indicating the presence of possible cluster expansion signatures. The ages of the majority of clusters demonstrating a general expansion at a 1\$\textbackslash sigma\$ confidence level are several tens of Myr, which is in agreement with the expected ages of OB associations. We found 32 open clusters which turned out to be members of the resulting groupings; their ages are consistent with one another within the uncertainties. Comparison of the clusters thus obtained with the historical composition of OB associations in the literature shows a correspondence between their positions in the Galaxy but an apparent absence of good one-to-one stellar matches. Therefore, we suggest that the historical composition of OB associations needs to be revised.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{chen_discovery_2020, title = {Discovery of New Stellar Groups in the {{Orion}} Complex}, author = {Chen, Boquan and D'Onghia, Elena and Alves, Jo{\~a}o and Adamo, Angela}, year = {2020}, month = jul, journal = {arXiv:1905.11429 [astro-ph]}, eprint = {1905.11429}, primaryclass = {astro-ph}, urldate = {2020-07-17}, abstract = {We test the ability of two unsupervised machine learning algorithms, \textbackslash textit\{EnLink\} and Shared Nearest Neighbour (SNN), to identify stellar groupings in the Orion star-forming complex as an application to the 5-dimensional astrometric data from \textbackslash textit\{Gaia\} DR2. The algorithms represent two distinct approaches to limiting user bias when selecting parameter values and evaluating the relative weights among astrometric parameters. \textbackslash textit\{EnLink\} adopts a locally adaptive distance metric and eliminates the need of parameter tuning through automation. The original SNN relies only on human input for parameter tuning so we modified SNN to run in two stages. We first ran the original SNN 7,000 times, each with a randomly generated sample according to within-source co-variance matrices provided in \textbackslash textit\{Gaia\} DR2 and random parameter values within reasonable ranges. During the second stage, we modified SNN to identify the most repeating stellar groups from 25,798 we obtained in the first stage. We reveal 21 spatially- and kinematically-coherent groups in the Orion complex, 12 of which previously unknown. The groups show a wide distribution of distances extending as far as about 150 pc in front of the star-forming Orion molecular clouds, to about 50 pc beyond them where we find, unexpectedly, several groups. Our results expose to view the wealth of sub-structure in the OB association, within and beyond the classical Blaauw Orion OBI sub-groups. A full characterization of the new groups is of the essence as it offers the potential to unveil how star formation proceeds globally in large complexes such as Orion. The data and code that generated the groups in this work as well as the final table can be found at \textbackslash protect\textbackslash url\{ https://github.com/BoquanErwinChen/GaiaDR2\_Orion\_Dissection\}.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\ZF4G3WPN\\1905.html}}
@article{cheng_testing_2020, title = {Testing the Chemical Homogeneity of Chemically-Tagged Dissolved Birth Clusters}, author = {Cheng, Chloe M. and {Price-Jones}, Natalie and Bovy, Jo}, year = {2020}, month = oct, journal = {arXiv:2010.09721 [astro-ph]}, eprint = {2010.09721}, primaryclass = {astro-ph}, urldate = {2020-10-21}, abstract = {Chemically tagging stars back to common formation sites in the Milky Way and establishing a high level of chemical homogeneity in these chemically-tagged birth clusters is important for understanding the chemical and dynamical history of the Galactic disc. We constrain the intrinsic abundance scatter in 17 newly chemically-tagged dissolved birth clusters found in the APOGEE survey by modeling APOGEE spectra as a one-dimensional function of initial stellar mass, performing forward modeling of the observed stellar spectra, and comparing the data and simulations using Approximate Bayesian Computation. We test this method on the well-known open clusters M67, NGC 6819, NGC 7789, and NGC 6791. We study 15 elements in APOGEE and find that, in general, we are able to obtain very strong constraints on the intrinsic abundance scatter of most elements in the chemically-tagged birth clusters, with upper limits of {$<\sptilde$} 0.02 dex for C, {$<\sptilde$} 0.03 dex for O, Mn, and Fe, {$<\sptilde$} 0.04 dex for Si and Ni, and {$<\sptilde$} 0.05 dex for N, Mg, and Ca. While we find some evidence for a small amount of chemical inhomogeneity in the remaining elements (i.e. Na, Al, S, K, Ti, and V), we are still able to obtain stronger limits compared to those found for open clusters, consistent with previous findings. By strongly constraining the level of chemical homogeneity within reconstructed birth clusters, we can strengthen the statement that these groups of stars represent birth clusters, with promising implications for future chemical tagging studies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JY8SHFHS\\2010.html}}
@article{chereul_distribution_1999, title = {The Distribution of Nearby Stars in Phase Space Mapped by {{Hipparcos}}. {{Clustering}} and Streaming among {{A-F}} Type Stars}, author = {Chereul, E. and Cr{\'e}z{\'e}, M. and Bienaym{\'e}, O.}, year = {1999}, month = feb, journal = {Astronomy and Astrophysics Supplement Series}, volume = {135}, pages = {5--28}, issn = {0365-0138}, doi = {10.1051/aas:1999160}, urldate = {2020-06-24}, abstract = {This paper presents the detailed results obtained in the search of density-velocity inhomogeneities in a volume limited and absolute magnitude limited sample of A-F type dwarfs within 125 parsecs of the Sun. A 3-D wavelet analysis is used to extract inhomogeneities, both in the density and velocity distributions. Thus, a real picture of the phase space is produced. Not only are some clusters and streams detected, but the fraction of clumped stars can be measured. By estimating individual stellar ages one can relate the streams and clusters to the state of the interstellar medium (ISM) at star formation time and provide a quantitative view of cluster evaporation and stream mixing. Having established this picture without assumption we come back to previously known observational facts regarding clusters and associations, moving groups or so-called superclusters. In the 3-D position space, well known open clusters (Hyades, Coma Berenices and Ursa Major), associations (parts of the Scorpio-Centaurus association) as well as the Hyades evaporation track are retrieved. Three new probably loose clusters are identified (Bootes, Pegasus 1 and 2). The sample is relatively well mixed in the position space since less than 7 per cent of the stars belong to structures with coherent kinematics, most likely gravitationally bound. The wavelet analysis exhibits strong velocity structuring at typical scales of velocity dispersion /line{$\sigma\_$}stream \textasciitilde{} 6.3, 3.8 and 2.4 km s(-1) . The majority of large scale velocity structures (/line{$\sigma\_$}stream \textasciitilde{} 6.3 km s(-1) ) are Eggen's superclusters (Pleiades SCl, Hyades SCl and Sirius SCl) with the whole Centaurus association. A new supercluster-like structure is found with a mean velocity between the Sun and Sirius SCl velocities. These structures are all characterized by a large age range which reflects the overall sample age distribution. Moreover, a few old streams of \textasciitilde{} 2 Gyr are also extracted at this scale with high U components. We show that all these large velocity dispersion structures represent 63\% of the sample. This percentage drops to 46\% if we remove the velocity background created by a smooth velocity ellipsoid in each structure. Smaller scales (/line{$\sigma\_$}stream \textasciitilde{} 3.8 and 2.4 km s(-1) ) reveal that superclusters are always substructured by 2 or more streams which generally exhibit a coherent age distribution. At these scales, background stars are negligible and percentages of stars in streams are 38\% and 18\% respectively. Based on data from the Hipparcos astrometry satellite.}, keywords = {GALAXIES OPEN CLUSTERS AND ASSOCIATIONS,GALAXIES: KINEMATICS AND DYNAMICS,GALAXY: SOLAR NEIGHBOURHOOD,METHODS: DATA ANALYSIS}}
@misc{chi_blind_search_2023, title = {Blind {{Search}} of {{The Solar Neighborhood Galactic Disk}} within 5kpc: 1,179 New {{Star}} Clusters Found in {{Gaia DR3}}}, shorttitle = {Blind {{Search}} of {{The Solar Neighborhood Galactic Disk}} within 5kpc}, author = {Chi, Huanbin and Wang, Feng and Wang, Wenting and Deng, Hui and Li, Zhongmu}, year = {2023}, month = mar, number = {arXiv:2303.10380}, eprint = {2303.10380}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.10380}, urldate = {2023-03-22}, abstract = {Studying open clusters (OCs) is essential for a comprehensive understanding of the structure and evolution of the Milky Way. Many previous studies have systematically searched for OCs near the solar system within 1.2 kpc or 20 degrees of galactic latitude. However, few studies searched for OCs at higher galactic latitudes and deeper distances. In this study, based on a hybrid unsupervised clustering algorithm (Friends-of-Friends and pyUPMASK) and a binary classification algorithm (Random Forest), we extended the search region (i.e., galactic latitude |b|{$>$}=20 degrees) and performed a fine-grained blind search of Galactic clusters in Gaia DR3. After cross-matching, the newly discovered cluster candidates are fitted using isochrone fitting to estimate the main physical parameters (age and metallicity) of these clusters. These cluster candidates were then checked using manual visual inspection. Their statistical properties were compared with previously exposed cluster catalogs as well. In the end, we found 1,179 new clusters with considerable confidence within 5kpc.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{chi_identify_2022, title = {Identify 46 {{New Open Clusters Candidates In Gaia EDR3 Using pyUPMASK}} and {{Random Forest Hybrid Method}}}, author = {Chi, Huanbin and Wei, Shoulin and Wang, Feng and Li, Zhongmu}, year = {2022}, month = dec, journal = {arXiv e-prints}, volume = {arXiv:2212.11569}, doi = {10.48550/arXiv.2212.11569}, urldate = {2023-02-20}, abstract = {Open clusters (OCs) are regarded as tracers to understand stellar evolution theory and validate stellar models. In this study, we presented a robust approach to identifying OCs. A hybrid method of pyUPMASK and RF is first used to remove field stars and determine more reliable members. An identification model based on the RF algorithm built based on 3714 OC samples from Gaia DR2 and EDR3 is then applied to identify OC candidates. The OC candidates are obtained after isochrone fitting, the advanced stellar population synthesis (ASPS) model fitting, and visual inspection. Using the proposed approach, we revisited 868 candidates and preliminarily clustered them by the friends-of-friends algorithm in Gaia EDR3. Excluding the open clusters that have already been reported, we focused on the remaining 300 unknown candidates. From high to low fitting quality, these unrevealed candidates were further classified into Class A (59), Class B (21), and Class C (220), respectively. As a result, 46 new reliable open cluster candidates among classes A and B are identified after visual inspection.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}}
@article{chi_lisc_2023, title = {{{LISC Catalog}} of {{Open Clusters}}.{{III}}. 83 {{Newly}} Found {{Galactic}} Disk Open Clusters Using {{Gaia EDR3}}}, author = {Chi, Huanbin and Wang, Feng and Li, Zhongmu}, year = {2023}, month = feb, journal = {arXiv e-prints}, volume = {arXiv:2302.08926}, doi = {10.48550/arXiv.2302.08926}, urldate = {2023-02-20}, abstract = {As groups of coeval stars born from the same molecular cloud, an Open cluster (OC) is an ideal laboratory for studying the structure and dynamical evolution of the Milky Way. The release of High-Precision Gaia Early Data Release 3 (Gaia EDR3) and modern machine-learning methods offer unprecedented opportunities to identify OCs. In this study, we extended conventional HDBSCAN (e-HDBSCAN) for searching for new OCs in Gaia EDR3. A pipeline was developed based on the parallel computing technique to blindly search for open clusters from Gaia EDR3 within Galactic latitudes \$\textbackslash left| b \textbackslash right|\$ \${$<\$$}25 \$\^\textbackslash circ\$. As a result, we obtained 3787 star clusters, of which 83 new OCs were reported after cross-match and visual inspection. At the same time, the main star cluster parameters are estimated by colour-magnitude diagram fitting. The study significantly increases the sample size and physical parameters of open clusters in the catalogue of OCs. It shows the incompleteness of the census of OCs across our Galaxy.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{choksi_initial_2019, title = {On the Initial Mass-Radius Relation of Stellar Clusters}, author = {Choksi, Nick and Kruijssen, J. M. Diederik}, year = {2019}, month = dec, journal = {arXiv:1912.05560 [astro-ph]}, eprint = {1912.05560}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {Young stellar clusters across nearly five orders of magnitude in mass appear to follow a simple mass-radius relationship (MRR), \$R\_\{\textbackslash star\} \textbackslash propto M\_\{\textbackslash star\}\^\{\textbackslash alpha\}\$, with \$\textbackslash alpha \textbackslash approx 0.2 - 0.33\$. Here, we develop a simple analytic model to explain this observation. We begin by considering giant molecular clouds near virial equilibrium and subsequently relate the properties of the cluster to those of the cloud. In turn, we relate the cloud properties to those of the large-scale galactic environment. The model predicts an \textbackslash textit\{initial\} mass-radius relation of constant surface density, \$R\_\{\textbackslash star\} \textbackslash propto M\_\{\textbackslash star\}\^\{1/2\}\$. It also predicts the initial cluster radius depends on the large-scale gas density \$\textbackslash Sigma\_g\$ of the ambient ISM, scaling as \$R\_\{\textbackslash star\} \textbackslash propto \textbackslash Sigma\_g\^\{-1/2\}\$. We argue that the tendency of observed clusters to fall along lines of shallower MRRs than our initial \$R\_\{\textbackslash star\} \textbackslash propto M\_\{\textbackslash star\}\^\{1/2\}\$ is in fact a combination of two effects. The fact that massive clusters can \textbackslash textit\{only\} form in high gas-density environments, when combined with the \$R\_\{\textbackslash star\} \textbackslash propto \textbackslash Sigma\_g\^\{-1/2\}\$ scaling we find here, ultimately shallows the global slope at high masses to nearly \$R\_\{\textbackslash star\} \textbackslash propto M\_\{\textbackslash star\}\^\{1/3\}\$. Meanwhile, at low masses relaxation-driven expansion quickly shallows the MRR. We combine our predicted MRR with a simple population synthesis model and apply it to a range of star-forming environments, from nearby disc galaxies to nuclear starbursts, and find good agreement throughout. We provide quantitative predictions for the radii of proto-globular clusters (GCs) and discuss the implications of the model for GC evolution and survival across cosmic time as well as the dynamical assembly of black hole binaries in stellar clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\B8NU6C8K\\1912.html}}
@misc{chollet_keras_2015, title = {Keras}, author = {Chollet, Fran{\c c}ois and others}, year = {2015}}
@article{claria_ccd_2019, title = {{{CCD Washington Photometry}} of {{Ten Open Clusters}} or {{Candidates Projected Close}} to the {{Galactic Plane}}}, author = {Clari{\'a}, J. J. and Parisi, M. C. and Palma, T. and Ahumada, A. V. and Oviedo, C. G.}, year = {2019}, month = mar, journal = {Acta Astronomica}, volume = {69}, pages = {1--23}, issn = {0001-5237}, doi = {10.32023/0001-5237/69.1.1}, urldate = {2020-06-24}, abstract = {We present high-quality CCD photometry in the Washington system C and T1 passbands down to T1{$\asymp$}19.5 mag in the fields of ten Galactic open clusters or candidates projected close to the Galactic plane, namely: ESO 313-SC03, BH 54, Ruprecht 87, ESO 129-SC32, BH 217, Collinder 347, Basel 5, Ruprecht 144, Archinal 1 and Berkeley 82. Four of these objects are located toward the Galactic center within a solid angle of 21\textdegree. No photoelectric or CCD photometry in the optical domain has been so far reported for five of these objects. Cluster radii are estimated from radial density profiles in the cluster fields. Using the cluster Washington (C-T1,T1) color-magnitude diagrams, statistically cleaned from field star contamination, we estimate reddening, heliocentric distance and age of the clusters by fitting Padova theoretical isochrones computed for the Washington system. In all cases, the best fittings were obtained with nearly solar metal content isochrones. Both radial density profiles and color-magnitude diagrams show that we are dealing with real open clusters, except for Ruprecht 87 and Archinal 1 that are found to be probably not physical systems. Differential reddening appears to be present across the fields of ESO 313-SC03, ESO 129-SC32, BH 217, Collinder 347 and Basel 5. The studied open clusters are located at d{$\odot$}=1.0-5.0 kpc from the Sun and at Galactocentric distances RGC=6.0-10.6 kpc, with mean reddening E(B-V) in the range of 0.10-1.30 mag and ages between 5 Myr (Collinder 347) and {$\asymp$}1000 Myr (Basel 5). The estimated linear cluster radii are in the range of 0.4-3.2 pc. In general terms, the results obtained show fairly good agreement with previous photometric results. In some clusters, however, considerable differences are found between the present results and previous ones determined using near-infrared photometric data. The current study provides new open cluster parameters and some revisions to the open cluster catalogs.}, keywords = {Archinal 1,Basel 5,Berkeley 82,BH 217,BH 54,Collinder 347,ESO 129-SC32,open clusters and associations: individual: ESO 313-SC03,Ruprecht 144,Ruprecht 87,Techniques: photometric}}
@article{cordoni_photometric_binaries_2023, title = {Photometric Binaries, Mass Functions, and Structural Parameters of 78 {{Galactic}} Open Clusters}, author = {Cordoni, Giacomo and Milone, Antonino P. and Marino, Anna F. and Vesperini, Enrico and Dondoglio, Emanuele and Legnardi, Maria Vittoria and Mohandasan, Anjana and Carlos, Marilia and Lagioia, Edoardo P. and Jang, Sohee and Ziliotto, Tuila}, year = {2023}, month = apr, journal = {Astronomy and Astrophysics}, volume = {672}, pages = {A29}, issn = {0004-6361}, doi = {10.1051/0004-6361/202245457}, urldate = {2023-04-10}, abstract = {Context. Binary stars play a crucial role in our understanding of the formation and evolution of star clusters and their stellar populations. Aims: We use Gaia Data Release 3 to homogeneously analyze 78 Galactic open clusters and the unresolved binary systems they host, each composed of two main sequence (MS) stars. Methods: We first investigated the structural parameters of these clusters, such as the core radius and the central density, and determined the cluster mass function (MF) and total mass by interpolating the density profile of each cluster. We measured the fraction of binaries with a large mass ratio and the fraction of blue straggler stars (BSSs), and finally investigated possible connections between the populations of binary stars and BSSs with the main parameters of the host cluster. Results: Remarkably, we find that the MFs of 78 analyzed open clusters follow a similar trend and are well reproduced by two single power-law functions, with a change in slope around masses of 1 M{$\odot$}. The fraction of binary stars ranges from {$\sim$}15\% to more than {$\sim$}60\% without significant correlation with the mass and the age of the host cluster. Moreover, we detect hints of a correlation between the total fraction of binary stars and the central density of the host cluster. We compared the fraction of binary stars with that of BSSs, finding that clusters with high and low central density exhibit different trends. The fraction of binaries does not significantly change with the mass of the primary star and the mass ratio. The radial distribution of binary stars depends on cluster age. The binaries of clusters younger than {$\sim$}800 Myr typically show a flat radial distribution, with some hints of a double peak. In contrast, the binaries of the remaining clusters are more centrally concentrated than the single stars, which is similar to what is observed in globular clusters. Full Tables C.1 and C.2 are only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/672/A29}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,binaries: close,Hertzsprung-Russell and C-M diagrams,mass function,open clusters and associations: general,stars: luminosity function,techniques: photometric}, annotation = {ADS Bibcode: 2023A\&A...672A..29C}}
@misc{cordoni_photometric_binaries_2023a, title = {Photometric Binaries, Mass Functions, and Structural Parameters of 78 {{Galactic}} Open Clusters}, author = {Cordoni, Giacomo and Milone, Antonino P. and Marino, Anna F. and Vesperini, Enrico and Dondoglio, Emanuele and Legnardi, Maria Vittoria and Mohandasan, Anjana and Carlos, Marilia and Lagioia, Edoardo P. and Jang, Sohee and Ziliotto, Tuila}, year = {2023}, month = feb, number = {arXiv:2302.03685}, eprint = {2302.03685}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2302.03685}, urldate = {2023-02-13}, abstract = {Binary stars play a crucial role in our understanding of the formation and evolution of star clusters and their stellar populations. We use Gaia Data Release 3 to homogeneously analyze 78 Galactic open clusters and the unresolved binary systems they host, each composed of two main sequence (MS) stars. We first investigated the structural parameters of these clusters, such as the core radius and the central density, and determined the cluster mass function (MF) and total mass by interpolating the density profile of each cluster. We measured the fraction of binaries with a large mass ratio and the fraction of blue straggler stars (BSSs), and finally investigated possible connections between the populations of binary stars and BSSs with the main parameters of the host cluster. \{Remarkably, we find that the MFs of 78 analyzed open clusters follow a similar trend and are well reproduced by two single power-law functions, with a change in slope around masses of 1\$M\_\{\textbackslash odot\}\$. The fraction of binary stars ranges from \$\textbackslash sim\$15\textbackslash\% to more than \$\textbackslash sim\$60\textbackslash\% without significant correlation with the mass and the age of the host cluster. Moreover, we detect hints of a correlation between the total fraction of binary stars and the central density of the host cluster. We compared the fraction of binary stars with that of BSSs, finding that clusters with high and low central density exhibit different trends. The fraction of binaries does not significantly change with the mass of the primary star and the mass ratio. The radial distribution of binary stars depends on cluster age. The binaries of clusters younger than \$\textbackslash sim\$800\textbackslash,Myr typically show a flat radial distribution, with some hints of a double peak. In contrast, the binaries of the remaining clusters are more centrally concentrated than the single stars, which is similar to what is observed in globular clusters.\vphantom\}}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{coronado_pearls_2021, title = {Pearls on a {{String}}: {{Numerous Stellar Clusters Strung}} along the {{Same Orbit}}}, shorttitle = {Pearls on a {{String}}}, author = {Coronado, Johanna and F{\"u}rnkranz, Verena and Rix, Hans-Walter}, year = {2021}, month = jun, journal = {arXiv:2107.00036 [astro-ph]}, eprint = {2107.00036}, primaryclass = {astro-ph}, urldate = {2021-07-21}, abstract = {Stars originate from the dense interstellar medium, which exhibits filamentary structure to scales of \$\textbackslash sim 1\$ kpc in galaxies like our Milky Way. We explore quantitatively how much resulting large-scale correlation there is among different stellar clusters and associations in \$\textbackslash textit\{orbit phase space\}\$, characterized here by actions and angles. As a starting point, we identified 55 prominent stellar overdensities in the 6D space of orbit (actions) and orbital phase (angles), among the \$\textbackslash sim\$ 2.8 million stars with radial velocities from Gaia EDR3 and \$d \textbackslash leq 800\$ pc. We then explored the orbital \$\textbackslash textit\{phase\}\$ distribution of all sample stars in the same \$\textbackslash textit\{orbit\}\$ patch as any one of these 55 overdensities. We find that very commonly numerous other distinct orbital phase overdensities exist along these same orbits, like pearls on a string. These `pearls' range from known stellar clusters to loose, unrecognized associations. Among orbit patches defined by one initial orbit-phase overdensity 50\% contain at least 8 additional orbital-phase pearls of 10 cataloged members; 20\% of them contain 20 additional pearls. This is in contrast to matching orbit patches sampled from a smooth mock catalog, or random nearby orbit patches, where there are only 2 (or 5, respectively) comparable pearls. Our findings quantify for the first time how common it is for star clusters and associations to form at distinct orbital phases of nearly the same orbit. This may eventually offer a new way to probe the 6D orbit structure of the filamentary interstellar medium.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5ZN39GBK\\2107.html}}
@article{cournoyer-cloutier_implementing_2020, title = {Implementing {{Primordial Binaries}} in {{Simulations}} of {{Star Cluster Formation}} with a {{Hybrid MHD}} and {{Direct N-Body Method}}}, author = {{Cournoyer-Cloutier}, Claude and Tran, Aaron and Lewis, Sean and Wall, Joshua E. and Harris, William E. and Mac Low, Mordecai-Mark and McMillan, Stephen L. W. and Zwart, Simon Portegies and Sills, Alison}, year = {2020}, month = nov, journal = {arXiv:2011.06105 [astro-ph]}, eprint = {2011.06105}, primaryclass = {astro-ph}, urldate = {2020-11-30}, abstract = {The fraction of stars in binary systems within star clusters is important for their evolution, but what proportion of binaries form by dynamical processes after initial stellar accretion remains unknown. In previous work, we showed that dynamical interactions alone produced too few low-mass binaries compared to observations. We therefore implement an initial population of binaries in the coupled MHD and direct N-body star cluster formation code Torch. We compare simulations with, and without, initial binary populations and follow the dynamical evolution of the binary population in both sets of simulations, finding that both dynamical formation and destruction of binaries take place. Even in the first few million years of star formation, we find that an initial population of binaries is needed at all masses to reproduce observed binary fractions for binaries with mass ratios above the \$q \textbackslash geq 0.1\$ detection limit. Our simulations also indicate that dynamical interactions in the presence of gas during cluster formation modify the initial distributions towards binaries with smaller primary masses, larger mass ratios, smaller semi-major axes and larger eccentricities. Systems formed dynamically do not have the same properties as the initial systems, and systems formed dynamically in the presence of an initial population of binaries differ from those formed in simulations with single stars only. Dynamical interactions during the earliest stages of star cluster formation are important for determining the properties of binary star systems.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SDS2HB4K\\2011.html}}
@article{crossland_towards_2019, title = {Towards {{Machine-assisted Meta-Studies}}: {{The Hubble Constant}}}, shorttitle = {Towards {{Machine-assisted Meta-Studies}}}, author = {Crossland, Tom and Stenetorp, Pontus and Riedel, Sebastian and Kawata, Daisuke and Kitching, Thomas D. and Croft, Rupert A. C.}, year = {2019}, month = dec, journal = {arXiv:1902.00027 [astro-ph]}, eprint = {1902.00027}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {We present an approach for automatic extraction of measured values from the astrophysical literature, using the Hubble constant for our pilot study. Our rules-based model -- a classical technique in natural language processing -- has successfully extracted 298 measurements of the Hubble constant, with uncertainties, from the 208,541 available arXiv astrophysics papers. We have also created an artificial neural network classifier to identify papers in arXiv which report novel measurements. From the analysis of our results we find that reporting measurements with uncertainties and the correct units is critical information when distinguishing novel measurements in free text. Our results correctly highlight the current tension for measurements of the Hubble constant and recover the \$3.5\textbackslash sigma\$ discrepancy -- demonstrating that the tool presented in this paper is useful for meta-studies of astrophysical measurements from a large number of publications.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Computer Science - Computation and Language}, file = {C\:\\Users\\Emily\\Zotero\\storage\\AIY2LVHD\\1902.html}}
@article{curtis_novae_spiral_1917, title = {Novae in the {{Spiral Nebulae}} and the {{Island Universe Theory}}}, author = {Curtis, Heber D.}, year = {1917}, month = oct, journal = {Publications of the Astronomical Society of the Pacific}, volume = {29}, pages = {206--207}, issn = {0004-6280}, doi = {10.1086/122632}, urldate = {2023-04-06}, annotation = {ADS Bibcode: 1917PASP...29..206C}}
@article{curtis_tess_2019, title = {{{TESS Reveals}} That the {{Nearby Pisces}}-{{Eridanus Stellar Stream}} Is Only 120 {{Myr Old}}}, author = {Curtis, Jason L. and Ag{\"u}eros, Marcel A. and Mamajek, Eric E. and Wright, Jason T. and Cummings, Jeffrey D.}, year = {2019}, month = aug, journal = {The Astronomical Journal}, volume = {158}, pages = {77}, doi = {10.3847/1538-3881/ab2899}, urldate = {2019-10-21}, abstract = {Pisces-Eridanus (Psc-Eri), a nearby (d {$\simeq$} 80-226 pc) stellar stream stretching across {$\approx$}120\textdegree{} of the sky, was recently discovered with Gaia data. The stream was claimed to be {$\approx$}1 Gyr old, which would make it an exceptional discovery for stellar astrophysics, as star clusters of that age are rare and tend to be distant, limiting their utility as benchmark samples. We test this old age for Psc-Eri in two ways. First, we compare the rotation periods for 101 low-mass members (measured using time-series photometry from the Transiting Exoplanet Survey Satellite) to those of well-studied open clusters. Second, we identify 34 new high-mass candidate members, including the notable stars {$\lambda$} Tauri (an Algol-type eclipsing binary) and HD 1160 (host to a directly imaged object near the hydrogen-burning limit). We conduct an isochronal analysis of the color-magnitude data for these highest-mass members, again comparing our results to those for open clusters. Both analyses show that the stream has an age consistent with that of the Pleiades, i.e., {$\approx$}120 Myr. This makes the Psc-Eri stream an exciting source of young benchmarkable stars and, potentially, exoplanets located in a more diffuse environment that is distinct from that of the Pleiades and of other dense star clusters.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HSZ6U5GD\\abstract.html}}
@article{dantona_role_dust_2023, title = {On the Role of Dust and Mass-Loss in the Extended Main Sequence Turnoff of Star Clusters: The Case of {{NGC}} 1783}, author = {D'Antona, F and Dell'Agli, F and Tailo, M and Milone, A P and Ventura, P and Vesperini, E and Cordoni, G and Dotter, A and Marino, A F}, year = {2023}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {521}, number = {3}, pages = {4462--4472}, issn = {0035-8711}, doi = {10.1093/mnras/stad851}, abstract = {The colour\textendash magnitude diagram (CMD) morphology of the `extended' main sequence turnoff (eMSTO) and upper main sequence (MS) of the intermediate age ({$\lessequivlnt$} 2 Gyr) Large Magellanic Cloud Cluster NGC 1783 shows the presence of a small group of UV-dim stars, that, in the ultraviolet Hubble Space Telescope filters, are located at colours on the red side of the typical `fan' shape displayed by the eMSTO. We model the UV-dim stars by assuming that some of the stars which would intrinsically be located on the left side of the eMSTO are obscured by a ring of dust due to grain condensation at the periphery of the excretion disc expelled when they spin at the high rotation rates typical of stars in the Be stage. A reasonably low optical depth at 10{$\mu$} is necessary to model the UV-dim group. Introduction of dust in the interpretation of the eMSTO may require a substantial re-evaluation of previous conclusions concerning the role of age and/or rotation spreads in the MC clusters: the entire eMSTO can be populated by dusty stars, and the reddest UV-dim stars simply represents the tail of the distribution with both maximum obscuration and the dust ring seen along the line of sight. The model stars having higher rotational projected velocity (vsin i) are predicted to be preferentially redder than the slowly rotating stars. The mass-loss responsible for the dust may also cause the non-monotonic distribution of stars in the upper main sequence, with two peaks and gaps showing up in the UV CMD.}}
@misc{de_andres_open_2022, title = {Open Clusters: Time-Scales, Core Collapse and Blue Stragglers}, shorttitle = {Open Clusters}, author = {{de Andr{\'e}s}, F{\'e}lix Llorente and {Morales-Dur{\'a}n}, Carmen}, year = {2022}, month = nov, number = {arXiv:2211.10915}, eprint = {2211.10915}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2211.10915}, urldate = {2022-12-13}, abstract = {We developed a mathematical model to derive time scales and the presence of BS stars. The model is based on the variation of mass through a circle into the cluster defined by a radius, and at a time; this mass cross is translated into a differential equation that it can be integrated for a given radius (r) and a determined time (t). From this equation we can derive the different time scales that allows us to reach conclusions like: clusters not containing blue strugglers (BS) stars disappear younger than those clusters containing BS. In clusters containing BS stars, the volume which takes up half of the cluster mass is bigger than the one corresponding to clusters without BS stars but the time to catch it up is shorter. We also studied, by means of this equation, the core collapse of stars of the cluster and the region where this concentration is stopped/retained; this region is identified by means of the relation \$c/ch\$, being \$c=\textbackslash log(rt/rc)\$ and \$ch=\textbackslash log(rc/rh)\$. Where rt and rc are the tidal and the core radius respectively, and rh is the radius where half of the cluster mass is concentrated. The model also drove us to the conclusion that the number of the blue straggler stars in a cluster follows a distribution function whose components are the ratio between relaxation time and the age, labelled as \$\textbackslash it f\$, and a factor, named \$\textbackslash varpi\$, which is an indicator of the origin of the BS; \$\textbackslash varpi\$ increases as the number of BS increase but it is limited to\$\textbackslash sim\$5.0. The mentioned distribution function is expressed as \$\textbackslash it NBS\$ \$\textbackslash sim\$ \$\textbackslash it f\^3\$(\$\textbackslash frac\{1\}\{e\^\{\textbackslash frac\{f\}\{\textbackslash varpi\}\}-1\}\$). The validity of this function was carried out by means of matching the number of observed blue straggler (BS) stars to the number of predicted ones in the available sample of OC.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@inproceedings{de_jong_4most_2012, title = {{{4MOST}}: 4-Metre Multi-Object Spectroscopic Telescope}, shorttitle = {{{4MOST}}}, booktitle = {\textbackslash procspie}, author = {{de Jong}, Roelof S. and {Bellido-Tirado}, Olga and Chiappini, Cristina and Depagne, {\'E}ric and Haynes, Roger and Johl, Diana and Schnurr, Olivier and Schwope, Axel and Walcher, Jakob and Dionies, Frank and Haynes, Dionne and Kelz, Andreas and Kitaura, Francisco S. and Lamer, Georg and Minchev, Ivan and M{\"u}ller, Volker and Nuza, {\relax Sebasti{\'a}n}. E. and Olaya, Jean-Christophe and Piffl, Tilmann and Popow, Emil and Steinmetz, Matthias and Ural, Ugur and Williams, Mary and Winkler, Roland and Wisotzki, Lutz and Ansorge, Wolfgang R. and Banerji, Manda and Gonzalez Solares, Eduardo and Irwin, Mike and Kennicutt, Robert C. and King, Dave and McMahon, Richard G. and Koposov, Sergey and Parry, Ian R. and Sun, David and Walton, Nicholas A. and Finger, Gert and Iwert, Olaf and Krumpe, Mirko and Lizon, Jean-Louis and Vincenzo, Mainieri and Amans, Jean-Philippe and Bonifacio, Piercarlo and Cohen, Mathieu and Francois, Patrick and Jagourel, Pascal and Mignot, Shan B. and Royer, Fr{\'e}d{\'e}ric and Sartoretti, Paola and Bender, Ralf and Grupp, Frank and Hess, Hans-Joachim and {Lang-Bardl}, Florian and Muschielok, Bernard and B{\"o}hringer, Hans and Boller, Thomas and Bongiorno, Angela and Brusa, Marcella and Dwelly, Tom and Merloni, Andrea and Nandra, Kirpal and Salvato, Mara and Pragt, Johannes H. and Navarro, Ram{\'o}n and Gerlofsma, Gerrit and Roelfsema, Ronald and Dalton, Gavin B. and Middleton, Kevin F. and Tosh, Ian A. and Boeche, Corrado and Caffau, Elisabetta and Christlieb, Norbert and Grebel, Eva K. and Hansen, Camilla and Koch, Andreas and Ludwig, Hans-G. and Quirrenbach, Andreas and Sbordone, Luca and Seifert, Walter and Thimm, Guido and Trifonov, Trifon and Helmi, Amina and Trager, Scott C. and Feltzing, Sofia and Korn, Andreas and Boland, Wilfried}, year = {2012}, month = sep, series = {Society of {{Photo-Optical Instrumentation Engineers}} ({{SPIE}}) {{Conference Series}}}, volume = {8446}, pages = {84460T}, address = {{eprint: arXiv:1206.6885}}, doi = {10.1117/12.926239}, urldate = {2020-06-24}, abstract = {The 4MOST consortium is currently halfway through a Conceptual Design study for ESO with the aim to develop a wide-field ( {$<$} 3 square degree, goal {$<$} 5 square degree), high-multiplex ( {$<$} 1500 fibres, goal 3000 fibres) spectroscopic survey facility for an ESO 4m-class telescope (VISTA). 4MOST will run permanently on the telescope to perform a 5 year public survey yielding more than 20 million spectra at resolution R{$\sim$}5000 ({$\lambda$}=390-1000 nm) and more than 2 million spectra at R\textasciitilde 20,000 (395-456.5 nm and 587-673 nm). The 4MOST design is especially intended to complement three key all-sky, space-based observatories of prime European interest: Gaia, eROSITA and Euclid. Initial design and performance estimates for the wide-field corrector concepts are presented. Two fibre positioner concepts are being considered for 4MOST. The first one is a Phi-Theta system similar to ones used on existing and planned facilities. The second one is a new R-Theta concept with large patrol area. Both positioner concepts effectively address the issues of fibre focus and pupil pointing. The 4MOST spectrographs are fixed configuration two-arm spectrographs, with dedicated spectrographs for the high- and low-resolution fibres. A full facility simulator is being developed to guide trade-off decisions regarding the optimal field-of-view, number of fibres needed, and the relative fraction of high-to-low resolution fibres. The simulator takes mock catalogues with template spectra from Design Reference Surveys as starting point, calculates the output spectra based on a throughput simulator, assigns targets to fibres based on the capabilities of the fibre positioner designs, and calculates the required survey time by tiling the fields on the sky. The 4MOST consortium aims to deliver the full 4MOST facility by the end of 2018 and start delivering high-level data products for both consortium and ESO community targets a year later with yearly increments.}}
@article{de_vazelhes_metric-learn_2019, title = {Metric-Learn: {{Metric Learning Algorithms}} in {{Python}}}, shorttitle = {Metric-Learn}, author = {{de Vazelhes}, William and Carey, C. J. and Tang, Yuan and Vauquier, Nathalie and Bellet, Aur{\'e}lien}, year = {2019}, month = aug, journal = {arXiv:1908.04710 [cs, stat]}, eprint = {1908.04710}, primaryclass = {cs, stat}, urldate = {2020-02-11}, abstract = {metric-learn is an open source Python package implementing supervised and weakly-supervised distance metric learning algorithms. As part of scikit-learn-contrib, it provides a unified interface compatible with scikit-learn which allows to easily perform cross-validation, model selection, and pipelining with other machine learning estimators. metric-learn is thoroughly tested and available on PyPi under the MIT licence.}, archiveprefix = {arxiv}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TCKNZPY2\\1908.html}}
@article{dejonghe_completely_analytical_1987, title = {A Completely Analytical Family of Anisotropic {{Plummer}} Models}, author = {Dejonghe, Herwig}, year = {1987}, month = jan, volume = {224}, pages = {13--39}, doi = {10.1093/mnras/224.1.13}, keywords = {Astronomical Models,Astrophysics,Eddington Approximation,Energy Distribution,Mass Distribution,Mass To Light Ratios,Poisson Equation,Spherical Coordinates,Stellar Systems}}
@misc{dellacroce_ongoing_hierarchical_2023, title = {Ongoing Hierarchical Massive Cluster Assembly: The {{LISCA II}} Structure in the {{Perseus}} Complex}, shorttitle = {Ongoing Hierarchical Massive Cluster Assembly}, author = {Della Croce, A. and Dalessandro, E. and Livernois, A. and Vesperini, E. and Fanelli, C. and Origlia, L. and Bellazzini, M. and Oliva, E. and Sanna, N. and Varri, A. L.}, year = {2023}, month = mar, journal = {arXiv e-prints}, doi = {10.48550/arXiv.2303.15501}, urldate = {2023-04-29}, abstract = {We report on the identification of a massive (\$\textbackslash sim10\^5\$ M\$\_\textbackslash odot\$) sub-structured stellar system in the Galactic Perseus complex likely undergoing hierarchical cluster assembly. Such a system comprises nine star clusters (including the well-known clusters NGC 654 and NGC 663) and an extended and low-density stellar halo. Gaia-DR3 and available spectroscopic data show that all its components are physically consistent in the 6D phase-space (position, parallax, and 3D motion), homogeneous in age (14 \$-\$ 44 Myr), and chemical content (half-solar metallicity). In addition, the system's global stellar density distribution is that of typical star clusters and shows clear evidence of mass segregation. We find that the hierarchical structure is mostly contracting towards the center with a speed of up to \$\textbackslash simeq4-5\$ km s\$\^\{-1\}\$, while the innermost regions expand at a lower rate (about \$\textbackslash simeq1\$ km s\$\^\{-1\}\$) and are dominated by random motions. Interestingly, this pattern is dominated by the kinematics of massive stars, while low-mass stars (\$M{$<$}2\$ M\$\_\textbackslash odot\$) are characterized by contraction across the entire cluster. Finally, the nine star clusters in the system are all characterized by a relatively flat velocity dispersion profile possibly resulting from ongoing interactions and tidal heating. We show that the observational results are generally consistent with those found in \$N\$-body simulations following the cluster violent relaxation phase strongly suggesting that the system is a massive cluster in the early assembly stages. This is the second structure with these properties identified in our Galaxy and, following the nomenclature of our previous work, we named it LISCA II.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, annotation = {ADS Bibcode: 2023arXiv230315501D}}
@misc{dellacroce_ongoing_hierarchical_2023a, title = {Ongoing Hierarchical Massive Cluster Assembly: The {{LISCA II}} Structure in the {{Perseus}} Complex}, shorttitle = {Ongoing Hierarchical Massive Cluster Assembly}, author = {Della Croce, A. and Dalessandro, E. and Livernois, A. and Vesperini, E. and Fanelli, C. and Origlia, L. and Bellazzini, M. and Oliva, E. and Sanna, N. and Varri, A. L.}, year = {2023}, month = mar, number = {arXiv:2303.15501}, eprint = {2303.15501}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.15501}, urldate = {2023-04-29}, abstract = {We report on the identification of a massive (\$\textbackslash sim10\^5\$ M\$\_\textbackslash odot\$) sub-structured stellar system in the Galactic Perseus complex likely undergoing hierarchical cluster assembly. Such a system comprises nine star clusters (including the well-known clusters NGC 654 and NGC 663) and an extended and low-density stellar halo. Gaia-DR3 and available spectroscopic data show that all its components are physically consistent in the 6D phase-space (position, parallax, and 3D motion), homogeneous in age (14 \$-\$ 44 Myr), and chemical content (half-solar metallicity). In addition, the system's global stellar density distribution is that of typical star clusters and shows clear evidence of mass segregation. We find that the hierarchical structure is mostly contracting towards the center with a speed of up to \$\textbackslash simeq4-5\$ km s\$\^\{-1\}\$, while the innermost regions expand at a lower rate (about \$\textbackslash simeq1\$ km s\$\^\{-1\}\$) and are dominated by random motions. Interestingly, this pattern is dominated by the kinematics of massive stars, while low-mass stars (\$M{$<$}2\$ M\$\_\textbackslash odot\$) are characterized by contraction across the entire cluster. Finally, the nine star clusters in the system are all characterized by a relatively flat velocity dispersion profile possibly resulting from ongoing interactions and tidal heating. We show that the observational results are generally consistent with those found in \$N\$-body simulations following the cluster violent relaxation phase strongly suggesting that the system is a massive cluster in the early assembly stages. This is the second structure with these properties identified in our Galaxy and, following the nomenclature of our previous work, we named it LISCA II.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{dempster_maximum_1977, title = {Maximum {{Likelihood}} from {{Incomplete Data Via}} the {{{\emph{EM}}}} {{Algorithm}}}, author = {Dempster, A. P. and Laird, N. M. and Rubin, D. B.}, year = {1977}, month = sep, journal = {Journal of the Royal Statistical Society: Series B (Methodological)}, volume = {39}, number = {1}, pages = {1--22}, issn = {00359246}, doi = {10.1111/j.2517-6161.1977.tb01600.x}, urldate = {2020-06-24}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\L5FP7QAP\\Dempster et al. - 1977 - Maximum Likelihood from Incomplete Data Via the i.pdf}}
@article{di_carlo_binary_2020, title = {Binary Black Holes in Young Star Clusters: The Impact of Metallicity}, shorttitle = {Binary Black Holes in Young Star Clusters}, author = {Di Carlo, Ugo N. and Mapelli, Michela and Giacobbo, Nicola and Spera, Mario and Bouffanais, Yann and Rastello, Sara and Santoliquido, Filippo and Pasquato, Mario and Ballone, Alessandro and Trani, Alessandro A. and Torniamenti, Stefano and Haardt, Francesco}, year = {2020}, month = apr, journal = {arXiv:2004.09525 [astro-ph]}, eprint = {2004.09525}, primaryclass = {astro-ph}, urldate = {2020-04-29}, abstract = {Young star clusters are the most common birth-place of massive stars and are dynamically active environments. Here, we study the formation of black holes (BHs) and binary black holes (BBHs) in young star clusters, by means of 6000 N-body simulations coupled with binary population synthesis. We probe three different stellar metallicities (Z=0.02, 0.002 and 0.0002) and two initial density regimes (density at the half-mass radius \$\textbackslash rho\_\{\textbackslash rm h\}\textbackslash ge\{\}3.4\textbackslash times10\^4\$ and \$\textbackslash ge\{1.5\textbackslash times10\^2\}\$ M\$\_\textbackslash odot\$ pc\$\^\{-3\}\$ in dense and loose star clusters, respectively). Metal-poor clusters tend to form more massive BHs than metal-rich ones. We find \$\textbackslash sim\{\}6\$, \$\textbackslash sim\{\}2\$, and \${$<$}1\$\% of BHs with mass \$m\_\{\textbackslash rm BH\}{$>$}60\$ M\$\_\textbackslash odot\$ at Z=0.0002, 0.002 and 0.02, respectively. In metal-poor clusters, we form intermediate-mass BHs with mass up to \$\textbackslash sim\{\}320\$ M\$\_\textbackslash odot\$. BBH mergers born via dynamical exchanges (exchanged BBHs) can be more massive than BBH mergers formed from binary evolution: the former (latter) reach total mass up to \$\textbackslash sim\{\}140\$ M\$\_\textbackslash odot\$ (\$\textbackslash sim\{\}80\$ M\$\_\textbackslash odot\$). The most massive BBH merger in our simulations has primary mass \$\textbackslash sim\{\}88\$ M\$\_\textbackslash odot\$, inside the pair-instability mass gap, and a mass ratio of \$\textbackslash sim\{\}0.5\$. Only BBHs born in young star clusters from metal-poor progenitors can match the masses of GW170729, the most massive event in O1 and O2, and those of GW190412, the first unequal-mass merger. We estimate a local BBH merger rate density \$\textbackslash sim\{\}110\$ and \$\textbackslash sim\{\}55\$ Gpc\$\^\{-3\}\$ yr\$\^\{-1\}\$, if we assume that all stars form in loose and dense star clusters, respectively.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - High Energy Astrophysical Phenomena,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\P9LD7TID\\2004.html}}
@article{di_carlo_intermediate_2021, title = {Intermediate Mass Black Holes from Stellar Mergers in Young Star Clusters}, author = {Di Carlo, Ugo N. and Mapelli, Michela and Pasquato, Mario and Rastello, Sara and Ballone, Alessandro and Dall'Amico, Marco and Giacobbo, Nicola and Iorio, Giuliano and Spera, Mario and Torniamenti, Stefano and Haardt, Francesco}, year = {2021}, month = may, journal = {arXiv:2105.01085 [astro-ph]}, eprint = {2105.01085}, primaryclass = {astro-ph}, urldate = {2021-05-05}, abstract = {Intermediate mass black holes (IMBHs) in the mass range \$10\^2-10\^5\textbackslash,\textbackslash mathrm\{M\_\{\textbackslash odot\}\}\$ bridge the gap between stellar black holes (BHs) and supermassive BHs. Here, we investigate the possibility that IMBHs form in young star clusters via runaway collisions and BH mergers. We analyze \$10\^4\$ simulations of dense young star clusters, featuring up-to-date stellar wind models and prescriptions for core collapse and (pulsational) pair instability. In our simulations, only 9 IMBHs out of 218 form via binary BH mergers, with a mass \$\textbackslash sim\{\}100-140\$ M\$\_\textbackslash odot\$. This channel is strongly suppressed by the low escape velocity of our star clusters. In contrast, IMBHs with masses up to \$\textbackslash sim\{\}438\$ M\$\_\{\textbackslash odot\}\$ efficiently form via runaway stellar collisions, especially at low metallicity. Up to \$\textbackslash sim\{\}0.2\$\textasciitilde\% of all the simulated BHs are IMBHs, depending on progenitor's metallicity. The runaway formation channel is strongly suppressed in metal-rich (\$Z=0.02\$) star clusters, because of stellar winds. IMBHs are extremely efficient in pairing with other BHs: \$\textbackslash sim\{\}70\$\% of them are members of a binary BH at the end of the simulations. However, we do not find any IMBH-BH merger. More massive star clusters are more efficient in forming IMBHs: \$\textbackslash sim\{\}8\$\% (\$\textbackslash sim\{\}1\$\%) of the simulated clusters with initial mass \$10\^4-3\textbackslash times\{\}10\^4\$ M\$\_\textbackslash odot\$ (\$10\^3-5\textbackslash times\{\}10\^3\$ M\$\_\textbackslash odot\$) host at least one IMBH.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - High Energy Astrophysical Phenomena,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M9LNXTXG\\2105.html}}
@article{dias_new_2002, title = {New Catalogue of Optically Visible Open Clusters and Candidates}, author = {Dias, W. S. and Alessi, B. S. and Moitinho, A. and L{\'e}pine, J. R. D.}, year = {2002}, month = jul, journal = {Astronomy and Astrophysics}, volume = {389}, pages = {871--873}, issn = {0004-6361}, doi = {10.1051/0004-6361:20020668}, urldate = {2020-06-24}, abstract = {We have compiled a new catalogue of open clusters in the Galaxy which updates the previous catalogues of Lyng\aa{} (\textbackslash cite\{Lynga1987\}) and of Mermilliod (\textbackslash cite\{Mermilliod1995\}) (included in the WEBDA database). New objects and new data, in particular, data on kinematics (proper motions) that were not present in the old catalogues, have been included. Virtually all the clusters (1537) presently known were included, which represents an increment of about 347 objects relative to the Lyng\aa{} (\textbackslash cite\{Lynga1987\}) catalogue. The catalogue is presented in a single table containing all the important data, which makes it easy to use. The catalogue can be accessed on line either at http://www.astro.iag.usp.br/\textasciitilde wilton/ or as an electronic table which will be made available at the CDS. Tables 1a, 1b, 2 and 3 are only available in electronic form at http://www.astro.iag.usp.br/wilton/, or at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/389/871}, keywords = {catalogs,galaxy: open clusters and associations: general}}
@misc{dickson_multimass_2023, title = {Multimass Modelling of {{Milky Way}} Globular Clusters -- {{I}}. {{Implications}} on Their Stellar Initial Mass Function above 1 {{M}}\$\_\{\textbackslash odot\}\$}, author = {Dickson, Nolan and {H{\'e}nault-Brunet}, Vincent and Baumgardt, Holger and Gieles, Mark and Smith, Peter}, year = {2023}, month = mar, number = {arXiv:2303.01637}, eprint = {2303.01637}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.01637}, urldate = {2023-03-07}, abstract = {The distribution of stars and stellar remnants (white dwarfs, neutron stars, black holes) within globular clusters holds clues about their formation and long-term evolution, with important implications for their initial mass function (IMF) and the formation of black hole mergers. In this work, we present best-fitting multimass models for 37 Milky Way globular clusters, which were inferred from various datasets, including proper motions from Gaia EDR3 and HST, line-of-sight velocities from ground-based spectroscopy and deep stellar mass functions from HST. We use metallicity dependent stellar evolution recipes to obtain present-day mass functions of stars and remnants from the IMF. By dynamically probing the present-day mass function of all objects in a cluster, including the mass distribution of remnants, these models allow us to explore in detail the stellar (initial) mass functions of a large sample of Milky Way GCs. We show that, while the low-mass mass function slopes are strongly dependent on the dynamical age of the clusters, the high-mass slope (\$\textbackslash alpha\_3; m {$>$} 1 M\_\textbackslash odot\$) is not, indicating that the mass function in this regime has generally been less affected by dynamical mass loss. Examination of this high-mass mass function slope suggests an IMF in this mass regime consistent with a Salpeter IMF is required to reproduce the observations. This high-mass IMF is incompatible with a top-heavy IMF, as has been proposed recently. Finally, no significant correlation is found between the high-mass IMF slope and cluster metallicity.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{dillon_tensorflow_2017, title = {{{TensorFlow Distributions}}}, author = {Dillon, Joshua V. and Langmore, Ian and Tran, Dustin and Brevdo, Eugene and Vasudevan, Srinivas and Moore, Dave and Patton, Brian and Alemi, Alex and Hoffman, Matt and Saurous, Rif A.}, year = {2017}, month = nov, journal = {arXiv e-prints}, volume = {arXiv:1711.10604}, urldate = {2022-04-04}, abstract = {The TensorFlow Distributions library implements a vision of probability theory adapted to the modern deep-learning paradigm of end-to-end differentiable computation. Building on two basic abstractions, it offers flexible building blocks for probabilistic computation. Distributions provide fast, numerically stable methods for generating samples and computing statistics, e.g., log density. Bijectors provide composable volume-tracking transformations with automatic caching. Together these enable modular construction of high dimensional distributions and transformations not possible with previous libraries (e.g., pixelCNNs, autoregressive flows, and reversible residual networks). They are the workhorse behind deep probabilistic programming systems like Edward and empower fast black-box inference in probabilistic models built on deep-network components. TensorFlow Distributions has proven an important part of the TensorFlow toolkit within Google and in the broader deep learning community.}, keywords = {Computer Science - Artificial Intelligence,Computer Science - Machine Learning,Computer Science - Programming Languages,Statistics - Machine Learning}}
@article{dinnbier_dynamical_2022, title = {On the Dynamical Evolution of {{Cepheids}} in Star Clusters}, author = {Dinnbier, Franti{\v s}ek and Anderson, Richard I. and Kroupa, Pavel}, year = {2022}, month = mar, journal = {Astronomy \& Astrophysics}, volume = {659}, eprint = {2112.09156}, pages = {A169}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202142134}, urldate = {2022-03-30}, abstract = {We investigate the occurrence of classical (type-I) Cepheid variable stars (henceforth: Cepheids) in dynamically evolving star clusters from birth to an age of approximately 300 Myr. The clusters are modelled by the Aarseth code nbody6, and they feature a realistic stellar initial mass function and initial binary star population, single star and binary star evolution, expulsion of the primordial gas, and the tidal field of the galaxy. Our simulations provide the first detailed dynamical picture of how frequently Cepheids remain gravitationally bound to their birth clusters versus how frequently they occur in the field. They allow us to quantify the relevance of various cluster escape mechanisms and how they depend on stellar mass. Overall, the simulations agree with the empirical picture that a small fraction (\$\textbackslash approx 10\textbackslash\%\$) of Cepheids reside in clusters, that cluster halo membership is relatively common, and that the majority of Cepheid hosting clusters have only a single Cepheid member. Additionally, the simulations predict that a) Cepheid progenitors are much more likely to escape from low-mass than higher-mass clusters; b) higher-mass (long-period) Cepheids are \$\textbackslash approx 30\textbackslash\%\$ more likely to be found in clusters than low-mass (short-period) Cepheids; c) the clustered Cepheid fraction increases with galactocentric radius since cluster dispersal is less efficient at greater radii; d) a lower metallicity reduces the overall clustered Cepheid fraction; e) high-mass clusters are much more likely to have more than one Cepheid member at any given time, in particular at a lower metallicity. We interpret the results as outcomes of various aspects of star cluster dynamics. The comparison of predicted and observed clustered Cepheid fractions, \$f\_\{\textbackslash rm CC\}\$, highlights the need for additional cluster disruption mechanisms, most likely encounters with giant molecular clouds.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{dinnbier_how_2020, title = {How Fast Do Young Star Clusters Expel Their Natal Gas?: {{Estimating}} the Upper Limit of the Gas Expulsion Time-Scale}, shorttitle = {How Fast Do Young Star Clusters Expel Their Natal Gas?}, author = {Dinnbier, F. and Walch, S.}, year = {2020}, month = aug, journal = {arXiv:2008.08602 [astro-ph]}, eprint = {2008.08602}, primaryclass = {astro-ph}, urldate = {2020-08-21}, abstract = {Formation of massive stars within embedded star clusters starts a complex interplay between their feedback, inflowing gas and stellar dynamics, which often includes close stellar encounters. Hydrodynamical simulations usually resort to substantial simplifications to model embedded clusters. Here, we address the simplification which approximates the whole star cluster by a single sink particle, which completely neglects the internal stellar dynamics. In order to model the internal stellar dynamics, we implement a Hermite predictor-corrector integration scheme to the hydrodynamic code FLASH. As we illustrate by a suite of tests, this integrator significantly outperforms the current leap-frog scheme, and it is able to follow the dynamics of small compact stellar systems without the necessity to soften the gravitational potential. We find that resolving individual massive stars instead of representing the whole cluster by a single energetic source has a profound influence on the gas component: for clusters of mass less than \$\textbackslash lesssim 3 \textbackslash times 10\^3 M\_\{\textbackslash odot\}\$, it slows gas expulsion by a factor of \$\textbackslash approx 5\$ to \$\textbackslash approx 1\$ Myr, and it results in substantially more complex gas structures. With increasing cluster mass (up to \$\textbackslash approx 3\textbackslash times 10\^3 M\_\{\textbackslash odot\}\$), the gas expulsion time-scale slightly decreases. However, more massive clusters (\$\textbackslash gtrsim 5\textbackslash times 10\^3 M\_\{\textbackslash odot\}\$) are unable to clear their natal gas with photoionising radiation and stellar winds only if they form with a star formation efficiency (SFE) of \$1/3\$. This implies that the more massive clusters are either cleared with another feedback mechanism or they form with a SFE higher than \$1/3\$.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\H9YTR5CT\\2008.html}}
@article{dinnbier_majority_2022, title = {Do the Majority of Stars Form as Gravitationally Unbound?}, author = {Dinnbier, Franti{\v s}ek and Kroupa, Pavel and Anderson, Richard I.}, year = {2022}, month = jan, journal = {arXiv:2201.06582 [astro-ph]}, eprint = {2201.06582}, primaryclass = {astro-ph}, urldate = {2022-01-25}, abstract = {Some of the youngest stars (age \$\textbackslash lesssim 10\$ Myr) are clustered, while many others are observed scattered throughout star forming regions or in complete isolation. It has been intensively debated whether the scattered or isolated stars originate in star clusters, or if they form truly isolated, which could help constrain the possibilities how massive stars are formed. We adopt the assumption that all stars form in gravitationally bound star clusters embedded in molecular cloud cores (\$\textbackslash Gamma\$-\$1\textbackslash;\$ model), which expel their natal gas, and compare the fraction of stars found in clusters with observational data. The star clusters are modelled by the code nbody6, which includes stellar and circumbinary evolution, gas expulsion, and the external gravitational field of their host galaxy. We find that small changes in the assumptions in the current theoretical model estimating the fraction, \$\textbackslash Gamma\$, of stars forming in embedded clusters have a large influence on the results, and we present a counterexample as an illustration. This calls into question theoretical arguments about \$\textbackslash Gamma\$ in embedded clusters, and it suggests that there is no firm theoretical ground for low \$\textbackslash Gamma\$ in galaxies with lower star formation rates (SFRs). Instead, the assumption that all stars form in embedded clusters is in agreement with observational data for the youngest stars (age \$\textbackslash lesssim 10\$ Myr). In the \$\textbackslash Gamma\$-\$1\textbackslash;\$ scenario, the observed fraction of the youngest stars in clusters increases with the SFR only weakly; the increase is caused by the presence of more massive clusters in galaxies with higher SFRs, which release fewer stars to the field in proportion to their mass. The \$\textbackslash Gamma\$-\$1\textbackslash;\$ model yields a higher fraction of stars in clusters for older stars (age between \$10\$ and \$300\$ Myr) than what is observed. This discrepancy can be caused by interactions with molecular clouds.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\F36VQDUA\\2201.html}}
@article{dinnbier_tidal_2020, title = {Tidal Tails of Open Star Clusters as Probes to Early Gas Expulsion. {{II}}. {{Predictions}} for {{Gaia}}}, author = {Dinnbier, Franti{\v s}ek and Kroupa, Pavel}, year = {2020}, month = aug, journal = {Astronomy and Astrophysics}, volume = {640}, pages = {A85}, issn = {0004-6361}, doi = {10.1051/0004-6361/201936572}, urldate = {2021-11-23}, abstract = {{$<$}BR /{$>$} Aims: We study the formation and evolution of the tidal tail released from a young star Pleiades-like cluster, due to expulsion of primordial gas in a realistic gravitational field of the Galaxy. The tidal tails (as well as clusters) are integrated from their embedded phase for 300 Myr. We vary star formation efficiencies (SFEs) from 33\% to 100\% and the timescales of gas expulsion as free parameters, and provide predictions for the morphology and kinematics of the evolved tail for each of the models. The resulting tail properties are intended for comparison with anticipated Gaia observations in order to constrain the poorly understood early conditions during the gas phase and gas expulsion. {$<$}BR /{$>$} Methods: The simulations are performed with the code NBODY6 including a realistic external gravitational potential of the Galaxy, and an analytical approximation for the natal gaseous potential. {$<$}BR /{$>$} Results: Assuming that the Pleiades formed with rapid gas expulsion and an SFE of {$\approx$}30\%, the current Pleiades are surrounded by a rich tail extending from {$\approx$}150 to {$\approx$}350 pc from the cluster and containing 0.7\texttimes{} to 2.7\texttimes{} the number of stars in the present-day cluster. If the Pleiades formed with an SFE close to 100\%, then the tail is shorter ({$\lessequivlnt$}90 pc) and substantially poorer with only {$\approx$}0.02\texttimes{} the number of present-day cluster stars. If the Pleiades formed with an SFE of {$\approx$}30\%, but the gas expulsion was adiabatic, the tail signatures are indistinguishable from the case of the model with 100\% SFE. The mass function of the tail stars is close to that of the canonical mass function for the clusters including primordial gas, but it is slightly depleted of stars more massive than {$\approx$}1 M\textsubscript{{$\odot$}} for the cluster with 100\% SFE, a difference that is not likely to be observed. The model takes into account the estimated contamination due to the field stars and the Hyades-Pleiades stream, which constitutes a more limiting factor than the accuracy of the Gaia measurements.}, langid = {english}}
@article{dinnbier_tidal_2020-1, title = {Tidal Tails of Open Star Clusters as Probes to Early Gas Expulsion {{I}}: {{A}} Semi-Analytic Model}, shorttitle = {Tidal Tails of Open Star Clusters as Probes to Early Gas Expulsion {{I}}}, author = {Dinnbier, Franti{\v s}ek and Kroupa, Pavel}, year = {2020}, month = jun, journal = {arXiv:2006.14087 [astro-ph]}, eprint = {2006.14087}, primaryclass = {astro-ph}, urldate = {2020-06-26}, abstract = {Context. Star clusters form out of the densest parts of infrared dark clouds. The emergence of massive stars expels the residual gas, which has not formed stars yet. Gas expulsion lowers the gravitational potential of the embedded cluster, unbinding many of the cluster stars. These stars then move on their own trajectories in the external gravitational field of the Galaxy, forming a tidal tail.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\PB4TPDDL\\Dinnbier and Kroupa - 2020 - Tidal tails of open star clusters as probes to ear.pdf}}
@article{divalentino_realm_hubble_2021, title = {In the Realm of the {{Hubble}} Tension-a Review of Solutions}, author = {Di Valentino, Eleonora and Mena, Olga and Pan, Supriya and Visinelli, Luca and Yang, Weiqiang and Melchiorri, Alessandro and Mota, David F. and Riess, Adam G. and Silk, Joseph}, year = {2021}, month = jul, journal = {Classical and Quantum Gravity}, volume = {38}, number = {15}, eprint = {2103.01183}, primaryclass = {astro-ph.CO}, pages = {153001}, doi = {10.1088/1361-6382/ac086d}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,cosmological parameters,cosmology,dark energy,General Relativity and Quantum Cosmology,High Energy Physics - Phenomenology,Hubble constant}}
@article{dobbs_formation_2022, title = {The Formation of Clusters and {{OB}} Associations in Different Density Spiral Arm Environments}, author = {Dobbs, C. L. and Bending, T. J. R. and Pettitt, A. R. and Buckner, A. S. M. and Bate, M. R.}, year = {2022}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2208.14930}, primaryclass = {astro-ph}, pages = {stac2474}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stac2474}, urldate = {2022-09-22}, abstract = {We present simulations of the formation and evolution of clusters in spiral arms. The simulations follow two different spiral arm regions, and the total gas mass is varied to produce a range of different mass clusters. We find that including photoionizing feedback produces the observed cluster mass radius relation, increasing the radii of clusters compared to without feedback. Supernovae have little impact on cluster properties. We find that in our high density, high gas mass simulations, star formation is less affected by feedback, as star formation occurs rapidly before feedback has much impact. In our lowest gas density simulation, the resulting clusters are completely different (e.g. the number of clusters and their masses) to the case with no feedback. The star formation rate is also significantly suppressed. The fraction of stars in clusters in this model decreases with time flattening at about 20\textbackslash\%. In our lowest gas simulation model, we see the formation of a star forming group with properties similar to an OB association, in particular similar to Orion Ia. We suggest that low densities, and stronger initial dynamics are conducive to forming associations rather than clusters. In all models cluster formation is complex with clusters merging and splitting. The most massive clusters which form have tended to undergo more mergers.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@misc{donada_multiplicity_2023, title = {The Multiplicity Fraction in 202 Open Clusters from {{Gaia}}}, author = {Donada, J. and Anders, F. and Jordi, C. and Masana, E. and Gieles, M. and Perren, G. and {Balaguer-N{\'u}{\~n}ez}, L. and {Castro-Ginard}, A. and {Cantat-Gaudin}, T. and Casamiquela, L.}, year = {2023}, month = jan, number = {arXiv:2301.11061}, eprint = {2301.11061}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2301.11061}, urldate = {2023-02-13}, abstract = {In this study, we estimate the fraction of binaries with high mass ratios for 202 open clusters in the extended solar neighbourhood (closer than 1.5 kpc from the Sun). This is one of the largest homogeneous catalogues of multiplicity fractions in open clusters to date, including the unresolved and total (close-binary) multiplicity fractions of main-sequence systems with mass ratio larger than \$0.6\_\{-0.15\}\^\{+0.05\}\$. The unresolved multiplicity fractions are estimated applying a flexible mixture model to the observed Gaia colour-magnitude diagrams of the open clusters. Then we use custom Gaia simulations to account for the resolved systems and derive the total multiplicity fractions. The studied open clusters have ages between 6.6 Myr and 3.0 Gyr and total high-mass-ratio multiplicity fractions between 6\% and 80\%, with a median of 18\%. The multiplicity fractions increase with the mass of the primary star, as expected. The average multiplicity fraction per cluster displays an overall decreasing trend with the open cluster age up to ages about 100 Myr, above which the trend increases. Our simulations show that most of this trend is caused by complex selection effects (introduced by the mass dependence of the multiplicity fraction and the magnitude limit of our sample). Furthermore, the multiplicity fraction is not significantly correlated with the clusters' position in the Galaxy. The spread in multiplicity fraction decreases significantly with the number of cluster members (used as a proxy for cluster mass). We also find that the multiplicity fraction decreases with metallicity, in line with recent studies using field stars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@misc{donada_multiplicity_fraction_2023, title = {The Multiplicity Fraction in 202 Open Clusters from {{Gaia}}}, author = {Donada, J. and Anders, F. and Jordi, C. and Masana, E. and Gieles, M. and Perren, G. and {Balaguer-N{\'u}{\~n}ez}, L. and {Castro-Ginard}, A. and {Cantat-Gaudin}, T. and Casamiquela, L.}, year = {2023}, month = jan, journal = {arXiv e-prints}, doi = {10.48550/arXiv.2301.11061}, urldate = {2023-04-10}, abstract = {In this study, we estimate the fraction of binaries with high mass ratios for 202 open clusters in the extended solar neighbourhood (closer than 1.5 kpc from the Sun). This is one of the largest homogeneous catalogues of multiplicity fractions in open clusters to date, including the unresolved and total (close-binary) multiplicity fractions of main-sequence systems with mass ratio larger than \$0.6\_\{-0.15\}\^\{+0.05\}\$. The unresolved multiplicity fractions are estimated applying a flexible mixture model to the observed Gaia colour-magnitude diagrams of the open clusters. Then we use custom Gaia simulations to account for the resolved systems and derive the total multiplicity fractions. The studied open clusters have ages between 6.6 Myr and 3.0 Gyr and total high-mass-ratio multiplicity fractions between 6\% and 80\%, with a median of 18\%. The multiplicity fractions increase with the mass of the primary star, as expected. The average multiplicity fraction per cluster displays an overall decreasing trend with the open cluster age up to ages about 100 Myr, above which the trend increases. Our simulations show that most of this trend is caused by complex selection effects (introduced by the mass dependence of the multiplicity fraction and the magnitude limit of our sample). Furthermore, the multiplicity fraction is not significantly correlated with the clusters' position in the Galaxy. The spread in multiplicity fraction decreases significantly with the number of cluster members (used as a proxy for cluster mass). We also find that the multiplicity fraction decreases with metallicity, in line with recent studies using field stars.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, annotation = {ADS Bibcode: 2023arXiv230111061D}}
@article{dondoglio_survey_2022, title = {Survey of Multiple Populations in Globular Clusters among Very Low-Mass Stars}, author = {Dondoglio, E. and Milone, A. P. and Renzini, A. and Vesperini, E. and Lagioia, E. P. and Marino, A. F. and Bellini, A. and Carlos, M. and Cordoni, G. and Jang, S. and Legnardi, M. V. and Libralato, M. and Mohandasan, A. and D'Antona, F. and Martorano, M. and Muratore, F. and Tailo, M.}, year = {2022}, month = jan, journal = {arXiv:2201.08631 [astro-ph]}, eprint = {2201.08631}, primaryclass = {astro-ph}, urldate = {2022-01-24}, abstract = {Recent work has shown that NIR Hubble Space Telescope (HST) photometry allows us to disentangle multiple populations (MPs) among M dwarfs of globular clusters (GCs) and investigate this phenomenon in very low-mass (VLM) stars. Here, we present the color-magnitude diagrams (CMDs) of nine GCs and the open cluster NGC 6791 in the F110W and F160W bands of HST, showing that the main sequences (MSs) below the knee are either broadened or split thus providing evidence of MPs among VLM stars. In contrast, the MS of NGC 6791 is consistent with a single population. The color distribution of M-dwarfs dramatically changes between different GCs and the color width correlates with the cluster mass. We conclude that the MP ubiquity, variety, and dependence on GC mass are properties common to VLM and more-massive stars. We combined UV, optical, and NIR observations of NGC 2808 and NGC 6121 (M 4) to identify MPs along with a wide range of stellar masses (\textasciitilde{} 0.2 - 0.8M ), from the MS turn off to the VLM regime, and measured, for the first time, their mass functions (MFs). We find that the fraction of MPs does not depend on the stellar mass and that their MFs have similar slopes. These findings indicate that the properties of MPs do not depend on stellar mass. In a scenario where the second generations formed in higher-density environments than the first generations, the possibility that the MPs formed with the same initial MF would suggest that it does not depend on the environment.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GWFA37L8\\2201.html}}
@article{donor_open_2018, title = {The {{Open Cluster Chemical Abundances}} and {{Mapping Survey}}. {{II}}. {{Precision Cluster Abundances}} for {{APOGEE Using SDSS DR14}}}, author = {Donor, John and Frinchaboy, Peter M. and Cunha, Katia and Thompson, Benjamin and O'Connell, Julia and Zasowski, Gail and Jackson, Kelly M. and McGrath, Brianne Meyer and Almeida, Andr{\'e}s and Bizyaev, Dmitry and Carrera, Ricardo and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Nitschelm, Christian and Pan, Kaike and Zamora, Olga}, year = {2018}, month = sep, journal = {The Astronomical Journal}, volume = {156}, number = {4}, pages = {142}, issn = {1538-3881}, doi = {10.3847/1538-3881/aad635}, urldate = {2019-10-18}, abstract = {The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to produce a comprehensive, uniform, infrared-based spectroscopic data set for hundreds of open clusters, and to constrain key Galactic dynamical and chemical parameters from this sample. This second contribution from the OCCAM survey presents analysis of 259 member stars with [Fe/H] determinations in 19 open clusters, using Sloan Digital Sky Survey Data Release 14 (SDSS/DR14) data from the Apache Point Observatory Galactic Evolution Experiment and ESA Gaia. This analysis, which includes clusters with R GC ranging from 7 to 13 kpc, measures an [Fe/H] gradient of -0.061 {$\pm$} 0.004 dex kpc-1. We also confirm evidence of a significant positive gradient in the {$\alpha$}-elements ([O/Fe], [Mg/Fe], and [Si/Fe]) and present evidence for a significant negative gradient in iron-peak elements ([Mn/Fe] and [Ni/Fe]).}, langid = {english}}
@article{donor_open_2020, title = {The {{Open Cluster Chemical Abundances}} and {{Mapping Survey}}: {{IV}}. {{Abundances}} for 128 {{Open Clusters}} Using {{SDSS}}/{{APOGEE DR16}}}, shorttitle = {The {{Open Cluster Chemical Abundances}} and {{Mapping Survey}}}, author = {Donor, John and Frinchaboy, Peter M. and Cunha, Katia and O'Connell, Julia E. and Prieto, Carlos Allende and Almeida, Andres and Anders, Friedrich and Beaton, Rachael and Bizyaev, Dmitry and Brownstein, Joel R. and Carrera, Ricardo and Chiappini, Cristina and Cohen, Roger and {Garcia-Hernandez}, D. A. and Geisler, Doug and Hasselquist, Sten and Jonsson, Henrik and Lane, Richard R. and Majewski, Steven R. and Minniti, Dante and Bidin, Christian Moni and Pan, Kaike and {Roman-Lopes}, Alexandre and Sobeck, Jennifer S. and Zasowski, Gail}, year = {2020}, month = feb, journal = {arXiv:2002.08980 [astro-ph]}, eprint = {2002.08980}, primaryclass = {astro-ph}, urldate = {2020-02-24}, abstract = {The Open Cluster Chemical Abundances and Mapping (OCCAM) survey aims to constrain key Galactic dynamical and chemical evolution parameters by the construction of a large, comprehensive, uniform, infrared-based spectroscopic data set of hundreds of open clusters. This fourth contribution from the OCCAM survey presents analysis using SDSS/APOGEE DR16 of a sample of 128 open clusters, 71 of which we designate to be "high quality" based on the appearance of their color-magnitude diagram. We find the APOGEE DR16 derived [Fe/H] abundances to be in good agreement with previous high resolution spectroscopic open cluster abundance studies. Using the high quality sample, we measure Galactic abundance gradients in 16 elements, and find evolution of some of the [X/Fe] gradients as a function of age. We find an overall Galactic [Fe/H] vs R\_GC gradient of \$-0.068 \textbackslash pm 0.001\$ dex kpc\$\^\{-1\}\$ over the range of \$6 {$<\$$} R\_GC \${$<$} 13.9\$ kpc; however, we note that this result is sensitive to the distance catalog used, varying as much as 15\%. We formally derive the location a break in the [Fe/H] abundance gradient as a free parameter in the gradient fit for the first time. We also measure significant Galactic gradients in O, Mg, S, Ca, Mn, Cr, Cu, Na, Al, and K, some of which are measured for the first time. Our large sample allows us to explore four well-populated age bins to explore the time evolution of gradients for a large number of elements and comment on possible implications for Galactic chemical evolution and radial migration.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\E3HDFT5S\\2002.html}}
@article{dreyer_new_general_1888a, title = {A {{New General Catalogue}} of {{Nebul\ae}} and {{Clusters}} of {{Stars}}, Being the {{Catalogue}} of the Late {{Sir John F}}. {{W}}. {{Herschel}}, {{Bart}}, Revised, Corrected, and Enlarged}, author = {Dreyer, J. L. E.}, year = {1888}, journal = {Memoirs of the Royal Astronomical Society}, volume = {49}, pages = {1}, urldate = {2020-06-24}, abstract = {Not Available}}
@article{dreyer_second_index_1910, title = {Second {{Index Catalogue}} of {{Nebul\ae}} and {{Clusters}} of {{Stars}}, Containing Objects Found in the Years 1895 to 1907; with {{Notes}} and {{Corrections}} to the {{New General Catalogue}} and to the {{Index Catalogue}} for 1888-94.}, author = {Dreyer, J. L. E.}, year = {1910}, month = jan, volume = {59}, pages = {105}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1910MmRAS..59..105D}}
@article{dropulic_machine_2021, title = {Machine {{Learning}} the 6th {{Dimension}}: {{Stellar Radial Velocities}} from {{5D Phase-Space Correlations}}}, shorttitle = {Machine {{Learning}} the 6th {{Dimension}}}, author = {Dropulic, Adriana and Ostdiek, Bryan and Chang, Laura J. and Liu, Hongwan and Cohen, Timothy and Lisanti, Mariangela}, year = {2021}, month = mar, journal = {arXiv:2103.14039 [astro-ph, physics:hep-ph, physics:physics]}, eprint = {2103.14039}, primaryclass = {astro-ph, physics:hep-ph, physics:physics}, urldate = {2021-03-30}, abstract = {The Gaia satellite will observe the positions and velocities of over a billion Milky Way stars. In the early data releases, the majority of observed stars do not have complete 6D phase-space information. In this Letter, we demonstrate the ability to infer the missing line-of-sight velocities until more spectroscopic observations become available. We utilize a novel neural network architecture that, after being trained on a subset of data with complete phase-space information, takes in a star's 5D astrometry (angular coordinates, proper motions, and parallax) and outputs a predicted line-of-sight velocity with an associated uncertainty. Working with a mock Gaia catalog, we show that the network can successfully recover the distributions and correlations of each velocity component for stars that fall within \$\textbackslash sim 5\$ kpc of the Sun. We also demonstrate that the network can accurately reconstruct the velocity distribution of a kinematic substructure in the stellar halo that is spatially uniform, even when it comprises a small fraction of the total star count.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,High Energy Physics - Phenomenology,{Physics - Data Analysis, Statistics and Probability}}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RNEXSM72\\2103.html}}
@article{duarte_how_2014, title = {How Well Does the {{Friends-of-Friends}} Algorithm Recover Group Properties from Galaxy Catalogs Limited in Both Distance and Luminosity?}, author = {Duarte, Manuel and Mamon, Gary}, year = {2014}, month = may, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {440}, number = {2}, eprint = {1401.0662}, pages = {1763--1778}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stu378}, urldate = {2020-06-24}, abstract = {We test the Friends-of-Friends (FoF) grouping algorithm, which depends on two linking lengths (LLs), plane-of-sky and line-of-sight (LOS), normalized to the mean nearest neighbor separation of field galaxies. We argue, on theoretical grounds, that LLs should be \$b\_\textbackslash perp \textbackslash simeq 0.11\$, and \$b\_\textbackslash parallel \textbackslash simeq 1.3\$ to recover 95\% of all galaxies with projected radii within the virial radius \$r\_\{200\}\$ and 95\% of the galaxies along the LOS. We then predict that 80 to 90\% of the galaxies in FoF groups should lie within their parent real-space groups (RSGs), defined within their virial spheres. We test the FoF extraction for 16x16 pairs of LLs, using subsamples of galaxies, doubly complete in distance and luminosity, of a flux-limited mock SDSS galaxy catalog. We find that massive RSGs are more prone to fragmentation, while the fragments typically have low estimated mass, with typically 30\% of groups of low and intermediate estimated mass being fragments. Group merging rises drastically with estimated mass. For groups of 3 or more galaxies, galaxy completeness and reliability are both typically better than 80\% (after discarding the fragments). Estimated masses of extracted groups are biased low, by up to a factor 4 at low richness, while the inefficiency of mass estimation improves from 0.85 dex to 0.2 dex when moving from low to high multiplicity groups. The optimal LLs depend on the scientific goal for the group catalog. We propose \$b\_\textbackslash perp \textbackslash simeq 0.07\$, with \$b\_\textbackslash parallel \textbackslash simeq 1.1\$ for studies of environmental effects, \$b\_\textbackslash parallel \textbackslash simeq 2.5\$ for cosmographic studies and \$b\_\textbackslash parallel \textbackslash simeq 5\$ for followups of individual groups.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\REBGMBIS\\1401.html}}
@article{dutra_new_2001, title = {New Infrared Star Clusters and Candidates in the {{Galaxy}} Detected with {{2MASS}}}, author = {Dutra, C. M. and Bica, E.}, year = {2001}, month = sep, journal = {Astronomy and Astrophysics}, volume = {376}, pages = {434--440}, issn = {0004-6361}, doi = {10.1051/0004-6361:20010978}, urldate = {2020-06-24}, abstract = {A sample of 42 new infrared star clusters, stellar groups and candidates was found throughout the Galaxy in the 2MASS J, H and especially KS atlases. In the Cygnus X region 19 new clusters, stellar groups and candidates were found as compared to 6 such objects in the previous literature. Colour-Magnitude Diagrams using the 2MASS Point Source Catalogue provided preliminary distance estimates in the range 1.0 {$<$} dsun {$<$} 1.8 kpc for 7 Cygnus X clusters. Towards the central parts of the Galaxy 7 new IR clusters and candidates were found as compared to 61 previous objects. A search for prominent dark nebulae in KS was also carried out in the central bulge area. We report 5 dark nebulae, 2 of them are candidates for molecular clouds able to generate massive star clusters near the Nucleus, such as the Arches and Quintuplet clusters.}, keywords = {GALAXY: OPEN CLUSTERS AND ASSOCIATIONS: INDIVIDUAL}}
@article{dutra_new_infrared_2003, title = {New Infrared Star Clusters in the Southern {{Milky Way}} with {{2MASS}}}, author = {Dutra, C. M. and Bica, E. and Soares, J. and Barbuy, B.}, year = {2003}, month = mar, journal = {Astronomy and Astrophysics}, volume = {400}, pages = {533--539}, issn = {0004-6361}, doi = {10.1051/0004-6361:20030005}, urldate = {2023-04-06}, abstract = {We carried out a 2MASS J, H and Ks survey of infrared star clusters in the Milky Way sector 230deg{$<$} l {$<$} 350deg. This zone was the least studied in the literature, previously including only 12 infrared clusters or stellar groups with |b|{$<$} 10deg, according to the recent catalogue by Bica et al. (2003). We concentrated efforts on embedded clusters, which are those expected in the areas of known radio and optical nebulae. The present study provides 179 new infrared clusters and stellar groups, which are interesting targets for detailed future infrared studies. The sample of catalogued infrared clusters and stellar groups in the Galaxy is now increased by 63\%.}, keywords = {Astrophysics,Galaxy: open clusters and associations: general,infrared: general}, annotation = {ADS Bibcode: 2003A\&A...400..533D}}
@article{el-badry_million_2021, title = {A Million Binaries from {{Gaia eDR3}}: Sample Selection and Validation of {{Gaia}} Parallax Uncertainties}, shorttitle = {A Million Binaries from {{Gaia eDR3}}}, author = {{El-Badry}, Kareem and Rix, Hans-Walter and Heintz, Tyler M.}, year = {2021}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {506}, pages = {2269--2295}, issn = {0035-8711}, doi = {10.1093/mnras/stab323}, urldate = {2022-01-20}, abstract = {We construct from Gaia eDR3 an extensive catalogue of spatially resolved binary stars within {$\asymp$}1 kpc of the Sun, with projected separations ranging from a few au to 1 pc. We estimate the probability that each pair is a chance alignment empirically, using the Gaia catalogue itself to calculate the rate of chance alignments as a function of observables. The catalogue contains 1.3 (1.1) million binaries with {$>$}90 per cent ({$>$}99 per cent) probability of being bound, including 16 000 white dwarf - main-sequence (WD + MS) binaries and 1400 WD + WD binaries. We make the full catalogue publicly available, as well as the queries and code to produce it. We then use this sample to calibrate the published Gaia DR3 parallax uncertainties, making use of the binary components' near-identical parallaxes. We show that these uncertainties are generally reliable for faint stars (G {$\greaterequivlnt$} 18), but are underestimated significantly for brighter stars. The underestimates are generally \$\textbackslash leq30\{\{\textbackslash{} \textbackslash rm per\textbackslash{} cent\}\}\$ for isolated sources with well-behaved astrometry, but are larger (up to \textasciitilde 80 per cent) for apparently well-behaved sources with a companion within {$\lessequivlnt$}4 arcsec, and much larger for sources with poor astrometric fits. We provide an empirical fitting function to inflate published {$\sigma\varpi$} values for isolated sources. The public catalogue offers wide ranging follow-up opportunities: from calibrating spectroscopic surveys, to precisely constraining ages of field stars, to the masses and the initial-final mass relation of WDs, to dynamically probing the Galactic tidal field.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,binaries: visual,catalogues,methods: statistical,parallaxes,stars: evolution}, annotation = {ADS Bibcode: 2021MNRAS.506.2269E}}
@inproceedings{ester_density-based_1996, title = {A {{Density-Based Algorithm}} for {{Discovering Clusters}} in {{Large Spatial Databases}} with {{Noise}}}, booktitle = {{{KDD-96 Proceedings}}}, author = {Ester, Martin and Kriegel, Hans-Peter and Xu, Xiaowei}, year = {1996}, pages = {6}, abstract = {Clusteringalgorithmasreattractivefor the taskof classidentification in spatial databases.Howevetrh, e applicationto large spatial databasesrises the followingrequirementfsor clustering algorithms: minimalrequirementsof domain knowledgteo determinethe input parameters,discoveryof clusters witharbitraryshapeandgoodefficiencyonlarge databases. Thewell-knowcnlusteringalgorithmsoffer nosolution to the combinatioonf theserequirementsI.n this paper, wepresent the newclustering algorithmDBSCAreNlying on a density-basednotionof clusters whichis designedto discoverclusters of arbitrary shape.DBSCrAeNquiresonly one input parameterandsupportsthe user in determiningan appropriatevaluefor it. Weperformeadn experimentaelvaluation of the effectiveness and efficiency of DBSCAusNing synthetic data and real data of the SEQUO2IA000benchmark.Theresults of our experimentsdemonstratethat (1) DBSCiAsNsignificantlymoreeffective in discoveringclusters of arbitrary shapethan the well-knowanlgorithmCLARANS,and that (2) DBSCAoNutperforms CLARANbyS factorof morethan100in termsof efficiency.}, langid = {english}}
@article{euclid_collaboration_euclid_2019, title = {{\emph{Euclid}} Preparation: {{III}}. {{Galaxy}} Cluster Detection in the Wide Photometric Survey, Performance and Algorithm Selection}, shorttitle = {{\emph{Euclid}} Preparation}, author = {{Euclid Collaboration} and Adam, R. and Vannier, M. and Maurogordato, S. and Biviano, A. and Adami, C. and Ascaso, B. and Bellagamba, F. and Benoist, C. and Cappi, A. and {D{\'i}az-S{\'a}nchez}, A. and Durret, F. and Farrens, S. and Gonzalez, A. H. and Iovino, A. and Licitra, R. and Maturi, M. and Mei, S. and Merson, A. and Munari, E. and Pell{\'o}, R. and Ricci, M. and Rocci, P. F. and Roncarelli, M. and Sarron, F. and Amoura, Y. and Andreon, S. and Apostolakos, N. and Arnaud, M. and Bardelli, S. and Bartlett, J. and Baugh, C. M. and Borgani, S. and Brodwin, M. and Castander, F. and Castignani, G. and Cucciati, O. and De Lucia, G. and Dubath, P. and Fosalba, P. and Giocoli, C. and Hoekstra, H. and Mamon, G. A. and Melin, J. B. and Moscardini, L. and Paltani, S. and Radovich, M. and Sartoris, B. and Schultheis, M. and Sereno, M. and Weller, J. and Burigana, C. and Carvalho, C. S. and Corcione, L. and {Kurki-Suonio}, H. and Lilje, P. B. and Sirri, G. and {Toledo-Moreo}, R. and Zamorani, G.}, year = {2019}, month = jul, journal = {Astronomy \& Astrophysics}, volume = {627}, pages = {A23}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201935088}, urldate = {2020-08-31}, abstract = {Galaxy cluster counts in bins of mass and redshift have been shown to be a competitive probe to test cosmological models. This method requires an efficient blind detection of clusters from surveys with a well-known selection function and robust mass estimates, which is particularly challenging at high redshift. The Euclid wide survey will cover 15 000 deg2 of the sky, avoiding contamination by light from our Galaxy and our solar system in the optical and near-infrared bands, down to magnitude 24 in the H-band. The resulting data will make it possible to detect a large number of galaxy clusters spanning a wide-range of masses up to redshift {$\sim$}2 and possibly higher. This paper presents the final results of the Euclid Cluster Finder Challenge (CFC), fourth in a series of similar challenges. The objective of these challenges was to select the cluster detection algorithms that best meet the requirements of the Euclid mission. The final CFC included six independent detection algorithms, based on different techniques, such as photometric redshift tomography, optimal filtering, hierarchical approach, wavelet and friend-of-friends algorithms. These algorithms were blindly applied to a mock galaxy catalog with representative Euclid-like properties. The relative performance of the algorithms was assessed by matching the resulting detections to known clusters in the simulations down to masses of M200 {$\sim$} 1013.25 M . Several matching procedures were tested, thus making it possible to estimate the associated systematic effects on completeness to {$<$}3\%. All the tested algorithms are very competitive in terms of performance, with three of them reaching {$>$}80\% completeness for a mean purity of 80\% down to masses of 1014 M and up to redshift z = 2. Based on these results, two algorithms were selected to be implemented in the Euclid pipeline, the Adaptive Matched Identifier of Clustered Objects (AMICO) code, based on matched filtering, and the PZWav code, based on an adaptive wavelet approach.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TZRHLJ37\\Euclid Collaboration et al_2019_iEuclid-i preparation.pdf}}
@article{evans_mass_2022-1, title = {Mass {{Segregation}} in the {{Hyades Cluster}}}, author = {Evans, N. Wyn and Oh, Semyeong}, year = {2022}, month = apr, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {512}, number = {3}, eprint = {2202.06973}, primaryclass = {astro-ph}, pages = {3846--3857}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stac707}, urldate = {2022-08-04}, abstract = {Using the Gaia colour-magnitude diagram, we assign masses to a catalogue of 979 confirmed members of the Hyades cluster and tails. By fitting the cumulative mass profile, stars within the tidal radius have a Plummer-like profile with half-mass radius \$r\_\{\textbackslash rm h\}\$ of 5.75 pc. The tails are extended with \$r\_\{\textbackslash rm h\} = 69.35\$ pc and fall off more slowly than Plummer with density proportional to distance\$\^\{-1.36\}\$. The cluster stars are separated into two groups at BP-RP \$=2\$ or \$0.56 M\_\textbackslash odot\$ to give a high mass (\$\{\textbackslash bar M\} = 0.95 M\_\textbackslash odot\$) and a low mass (\$\{\textbackslash bar M\} = 0.32 M\_\textbackslash odot\$) population. We show that: (i) the high mass population has a half-mass radius \$r\_\{\textbackslash rm h\}\$ of 4.88 pc, whilst the low mass population has \$r\_\{\textbackslash rm h\} = 8.10\$ pc; (ii) despite the differences in spatial extent, the kinematics and binarity properties of the high and low mass populations are similar. They have isotropic velocity ellipsoids with mean 1d velocity dispersions \$\textbackslash sigma\$ of 0.427 and 0.415 km s\$\^\{-1\}\$ respectively. The dynamical state of the Hyades is far from energy equipartition (\$\textbackslash sigma \textbackslash propto \{\textbackslash bar M\}\^\{-1/2\}\$). We identify a new mass segregation instability for clusters with escape speed \$V\$. Populations with \$V/\textbackslash sigma \textbackslash lesssim 2\textbackslash sqrt\{2\}\$ can never attain thermal equilibrium and equipartition. This regime encompasses many Galactic open and globular clusters. For the Hyades, there must be an outward energy flux of at least \$9.5 \textbackslash times 10\^\{-4\} M\_\textbackslash odot\textbackslash,\{\textbackslash rm km\^2\textbackslash, s\^\{-2\} Myr\^\{-1\}\}\$ to maintain its current configuration. The present mass loss of \$0.26 M\_\textbackslash odot \{\textbackslash rm Myr\}\^\{-1\}\$ due to tidal stripping by itself implies a substantial energy flow beyond the required magnitude.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{everall_completeness_2022, title = {Completeness of the {{Gaia}} Verse - {{V}}. {{Astrometry}} and Radial Velocity Sample Selection Functions in {{Gaia EDR3}}}, author = {Everall, Andrew and Boubert, Douglas}, year = {2022}, month = feb, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {509}, pages = {6205--6224}, issn = {0035-8711}, doi = {10.1093/mnras/stab3262}, urldate = {2022-01-11}, abstract = {We risk reaching false scientific conclusions if we test our physical theories against subsets of the Gaia catalogue without correcting for the biased process by which stars make it into our sample. In this paper, we produce selection functions for three Gaia science samples to enable the community to correct for this bias. We estimate the probability that a source in Gaia EDR3 will have (i) a reported parallax and proper motion, (ii) an astrometric renormalized unit weight error below 1.4, or (iii) a reported radial velocity. These SELECTIONFUNCTIONS are estimated as a function of G-band apparent magnitude and position on the sky, with the latter two also being dependent on G - GRP colour. The inferred selection functions have a non-trivial dependence on these observable parameters, demonstrating the importance of empirically estimating selection functions. We also produce a simple estimate for the selection function of the full Gaia EDR3 source catalogue to be used with the subset selection functions. We make all of our selection functions easily accessible through the GitHub repository SELECTIONFUNCTIONS.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics,Galaxy: kinematics and dynamics,Galaxy: stellar content,methods: data analysis,methods: statistical,stars: statistics}, annotation = {ADS Bibcode: 2022MNRAS.509.6205E}}
@article{fan_stellar_2021, title = {The {{Stellar}} "{{Snake}}" {{I}}: {{Whole Structure}} and {{Properties}}}, shorttitle = {The {{Stellar}} "{{Snake}}" {{I}}}, author = {Fan, Wang and {Hai-Jun}, Tian and Dan, Qiu and Qi, Xu and Min, Fang and Hao, Tian and Di, Li and Bird, Sarah and {Jian-Rong}, Shi and {Xiao-Ting}, Fu and {Gao-Chao}, Liu and Sheng, Cui and Yong, Zhang}, year = {2021}, month = sep, journal = {arXiv:2109.05999 [astro-ph]}, eprint = {2109.05999}, primaryclass = {astro-ph}, urldate = {2021-09-15}, abstract = {To complement our previous discovery of the young snake-like structure in the solar neighborhood and reveal the structure's full extent, we explore \{\textbackslash tt Gaia EDR3\} data within and surround the "snake" territory. With the friends-of-friends algorithm, we identify 2694 and 9615 Snake member candidates from the two samples. Thirteen open clusters are embedded in these member candidates. By combining the spectroscopic data from multiple surveys, we investigate the comprehensive properties of the candidates and find that they actually belong to one sizable structure, since most of the components are well bridged in their spatial distributions, and follow a single stellar population with an age of \$30-40\$\textbackslash,Myr and with solar metallicity. This sizable structure should be a hierarchically primordial structure, and probably formed from a filamentary giant molecular cloud with different formation history in the local regions. The whole structure is expanding. To further analyze the dynamics of the Snake, we divide the structure into five groups according to their tangential kinematics. We find that the groups are expanding at a coherent rate (\$\textbackslash kappa\_X\textbackslash sim3.0\textbackslash,\textbackslash times10\^\{-2\}\textbackslash,\textbackslash rm km\textbackslash,s\^\{-1\}\textbackslash,pc\^ \{-1\}\$) in along the length of the structure (\$X\$ direction). With over ten thousand member stars, the Snake is an ideal laboratory to study nearby coeval stellar formation, stellar physics, and environmental evolution over a large spatial extent.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M9ZGTYLH\\2109.html}}
@article{ferreira_cosmological_2019, title = {Cosmological {{Tests}} of {{Gravity}}}, author = {Ferreira, Pedro G}, year = {2019}, pages = {42}, langid = {english}, file = {/home/ehunt/Zotero/storage/3DZ2SH7H/Ferreira_2019_Cosmological Tests of Gravity_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\3DZ2SH7H\\Ferreira_2019_Cosmological Tests of Gravity.pdf}}
@article{ferreira_discovery_2020, title = {Discovery and Astrophysical Properties of {{Galactic}} Open Clusters in Dense Stellar Fields Using {{Gaia DR2}}}, author = {Ferreira, Filipe A. and Santos Jr., J. F. C. and Corradi, W. J. B. and Maia, F. F. S. and Angelo, M. S.}, year = {2020}, month = jun, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {496}, number = {2}, eprint = {2006.05611}, pages = {2021--2038}, urldate = {2020-06-15}, abstract = {We report the discovery of 25 new open clusters resulting from a search in dense low galactic latitude fields. We also provide, for the first time, structural and astrophysical parameters for the new findings and 34 other recently discovered open clusters using Gaia DR2 data. The candidates were confirmed by jointly inspecting the vector point diagrams and spatial distribution. The discoveries were validated by matching near known objects and comparing their mean astrometric parameters with the available literature. A decontamination algorithm was applied to the three-dimensional astrometric space to derive membership likelihoods for clusters stars. By rejecting stars with low membership likelihoods, we built decontaminated colour-magnitude diagrams and derived the clusters astrophysical parameters by isochrone fitting. The structural parameters were also derived by King-profile fittings over the stellar distributions. The investigated clusters are mainly located within 3 kpc from the Sun, with ages ranging from 30 Myr to 3.2 Gyr and reddening limited to E(B-V)=2.5. On average, our cluster sample presents less concentrated structures than Gaia DR2 confirmed clusters, since the derived core radii are larger while the tidal radii are not significantly different. Most of them are located in the IV quadrant of the Galactic disc at low latitudes, therefore they are immersed in dense fields characteristic of the inner Milky Way.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NHAQK26R\\2006.html}}
@article{ferreira_new_2021, title = {New Star Clusters Discovered towards the {{Galactic}} Bulge Direction Using {{Gaia DR2}}}, author = {Ferreira, F. A. and Corradi, W. J. B. and Maia, F. F. S. and Angelo, M. S. and Santos, Jr., J. F. C.}, year = {2021}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {502}, pages = {L90-L94}, issn = {0035-8711}, doi = {10.1093/mnrasl/slab011}, urldate = {2022-03-28}, abstract = {We report the discovery of 34 new open clusters and candidates as a result of a systematic search carried out in 200 adjacent fields of 1 \texttimes{} 1 deg2 area projected towards the Galactic bulge, using Gaia DR2 data. The objects were identified and characterized by a joint analysis of their photometric, kinematic, and spatial distribution that has been consistently used and proved to be effective in our previous works. The discoveries were validated by cross-referencing the objects position and astrometric parameters with the available literature. Besides their coordinates and astrometric parameters, we also provide sizes, ages, distances, and reddening for the discovered objects. In particular, 32 clusters are closer than 2 kpc from the Sun, which represents an increment of nearly \$39\{\{\textbackslash{} \textbackslash rm per\textbackslash{} cent\}\}\$ of objects with astrophysical parameters determined in the nearby inner disc. Although these objects fill an important gap in the open clusters distribution along the Sagittarius arm, this arm, traced by known clusters, appears to be interrupted, which may be an artefact due to the incompleteness of the cluster census.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Galaxy: stellar content,open clusters and associations: general}, annotation = {ADS Bibcode: 2021MNRAS.502L..90F}}
@article{ferreira_three_2019, title = {Three New {{Galactic}} Star Clusters Discovered in the Field of the Open Cluster {{NGC}} 5999 with {{Gaia DR2}}}, author = {Ferreira, Filipe A. and Santos, J. F. C. and Corradi, W. J. B. and Maia, F. F. S. and Angelo, M. S.}, year = {2019}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {483}, pages = {5508--5517}, issn = {0035-8711}, doi = {10.1093/mnras/sty3511}, urldate = {2022-03-28}, abstract = {We report the serendipitous discovery of three new open clusters, named UFMG 1, UFMG 2, and UFMG 3 in the field of the intermediate-age cluster NGC 5999, by using Gaia DR2 data. A colour-magnitude filter tailored for a proper selection of main-sequence stars and red clump giants turned evident the presence of NGC 5999 and these three new stellar groups in proper motion space. Their structural parameters were derived from King-profile fittings over their projected stellar distributions and isochrone fits were performed on the clusters cleaned colour-magnitude diagrams built with Gaia bands to derive their astrophysical parameters. The clusters projected sky motions were calculated for each target using our members' selection. Distances to the clusters were inferred from stellar parallaxes through a Bayesian model, showing that they are marginally consistent with their isochronal distances, considering the random and systematic uncertainties involved. The new clusters are located in the nearby Sagittarius arm (d {$\sim$} 1.5 kpc) with NGC 5999 at the background (d {$\sim$} 1.8 kpc). They contain at least a few hundred stars of nearly solar metallicity and have ages between 100 and 1400 Myr.}, keywords = {Astrophysics - Astrophysics of Galaxies,Galaxy: stellar content,open clusters and associations: general}, annotation = {ADS Bibcode: 2019MNRAS.483.5508F}}
@article{foreman-mackey_emcee_2013, title = {Emcee: {{The MCMC Hammer}}}, shorttitle = {Emcee}, author = {{Foreman-Mackey}, Daniel and Hogg, David W. and Lang, Dustin and Goodman, Jonathan}, year = {2013}, month = mar, journal = {Publications of the Astronomical Society of the Pacific}, volume = {125}, number = {925}, eprint = {1202.3665}, pages = {306--312}, issn = {00046280, 15383873}, doi = {10.1086/670067}, urldate = {2022-04-04}, abstract = {We introduce a stable, well tested Python implementation of the affine-invariant ensemble sampler for Markov chain Monte Carlo (MCMC) proposed by Goodman \& Weare (2010). The code is open source and has already been used in several published projects in the astrophysics literature. The algorithm behind emcee has several advantages over traditional MCMC sampling methods and it has excellent performance as measured by the autocorrelation time (or function calls per independent sample). One major advantage of the algorithm is that it requires hand-tuning of only 1 or 2 parameters compared to \$\textbackslash sim N\^2\$ for a traditional algorithm in an N-dimensional parameter space. In this document, we describe the algorithm and the details of our implementation and API. Exploiting the parallelism of the ensemble method, emcee permits any user to take advantage of multiple CPU cores without extra effort. The code is available online at http://dan.iel.fm/emcee under the MIT License.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Physics - Computational Physics,Statistics - Computation}}
@article{friel_metallicities_2002, title = {Metallicities of {{Old Open Clusters}}*}, author = {Friel, Eileen D. and Janes, Kenneth A. and Tavarez, Maritza and Scott, Jennifer and Katsanis, Rocio and Lotz, Jennifer and Hong, Linh and Miller, Nathan}, year = {2002}, month = nov, journal = {The Astronomical Journal}, volume = {124}, number = {5}, pages = {2693}, issn = {1538-3881}, doi = {10.1086/344161}, urldate = {2019-09-19}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HNKNC8QN\\Friel et al. - 2002 - Metallicities of Old Open Clusters.pdf;C\:\\Users\\Emily\\Zotero\\storage\\M99JYRUC\\344161.html}}
@article{fritz_gaia_dr2_2018, title = {Gaia {{DR2}} Proper Motions of Dwarf Galaxies within 420 Kpc. {{Orbits}}, {{Milky Way}} Mass, Tidal Influences, Planar Alignments, and Group Infall}, author = {Fritz, T. K. and Battaglia, G. and Pawlowski, M. S. and Kallivayalil, N. and {van der Marel}, R. and Sohn, S. T. and Brook, C. and Besla, G.}, year = {2018}, month = nov, volume = {619}, eprint = {1805.00908}, primaryclass = {astro-ph.GA}, pages = {A103}, doi = {10.1051/0004-6361/201833343}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2018A\&A...619A.103F}, archiveprefix = {arxiv}, eid = {A103}, keywords = {Astrophysics - Astrophysics of Galaxies,galaxies: dwarf,galaxies: kinematics and dynamics,Galaxy: evolution,Local Group,proper motions}}
@article{froebrich_new_2017, title = {New Compact Star Cluster Candidates in the {{Galactic}} Plane}, author = {Froebrich, D.}, year = {2017}, month = aug, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {469}, number = {2}, pages = {1545--1552}, issn = {0035-8711}, doi = {10.1093/mnras/stx938}, urldate = {2019-09-03}, abstract = {Abstract. The sample of known star clusters, the fundamental building blocks of galaxies, in the Milky Way is still extremely incomplete for objects beyond a d}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\J8DJ9BUS\\Froebrich - 2017 - New compact star cluster candidates in the Galacti.pdf;C\:\\Users\\Emily\\Zotero\\storage\\S75LZMV7\\3744463.html}}
@article{froebrich_systematic_2007, title = {A Systematic Survey for Infrared Star Clusters with |b| {$<$}20\textdegree{} Using {{2MASS}}}, author = {Froebrich, D. and Scholz, A. and Raftery, C. L.}, year = {2007}, month = jan, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {374}, pages = {399--408}, doi = {10.1111/j.1365-2966.2006.11148.x}, urldate = {2020-10-19}, abstract = {We used star density maps obtained from the Two-Micron All-Sky Survey (2MASS) to obtain a sample of star clusters in the entire Galactic Plane with |b| {$<$} 20\textdegree. A total of 1788 star cluster candidates are identified in this survey. Among those are 681 previously known open clusters and 86 globular clusters. A statistical analysis indicates that our sample of 1021 new cluster candidates has a contamination of about 50per cent. Star cluster parameters are obtained by fitting a King profile to the star density. These parameters are used to statistically identify probable new globular cluster candidates in our sample. A detailed investigation of the projected distribution of star clusters in the Galaxy demonstrates that they show a clear tendency to cluster on spatial scales in the order of 12-25pc, a typical size for molecular clouds.}, keywords = {globular clusters: general,methods: statistical,open clusters and associations: general}}
@misc{fu_lamost_2022, title = {{{LAMOST}} Meets {{Gaia}}: {{The Galactic Open Clusters}}}, shorttitle = {{{LAMOST}} Meets {{Gaia}}}, author = {Fu, Xiaoting and Bragaglia, Angela and Liu, Chao and Zhang, Huawei and Xu, Yan and Wang, Ke and Zhang, Zhi-Yu and Zhong, Jing and Chang, Jiang and Li, Lu and Chen, Li and Chen, Yang and Wang, Fei and Gjergo, Eda and Wang, Chun and Yue, Nannan and Zhang, Xi}, year = {2022}, month = jul, number = {arXiv:2207.09121}, eprint = {2207.09121}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2207.09121}, urldate = {2022-07-26}, abstract = {Open Clusters are born and evolve along the Milky Way plane, on them is imprinted the history of the Galactic disc, including the chemical and dynamical evolution. Chemical and dynamical properties of open clusters can be derived from photometric, spectroscopic, and astrometric data of their member stars. Based on the photometric and astrometric data from the Gaia mission, the membership of stars in more than 2000 Galactic clusters has been identified in the literature. The chemical and kinematical properties, however, are still poorly known for many of these clusters. In synergy with the large spectroscopic survey LAMOST (data release 8) and Gaia (data release 2), we report a new comprehensive catalogue of 386 open clusters. This catalogue has homogeneous parameter determinations of radial velocity, metallicity, and dynamical properties, such as orbit, eccentricity, angular momenta, total energy, and 3D Galactic velocity. These parameters allow the first radial velocity determination and the first spectroscopic [Fe/H] determination for 44 and 137 clusters, respectively. The metallicity distribution of majority clusters shows falling trends in the parameter space of the Galactocentric radius, the total energy, and the Z component of angular momentum -- except for two old groups that show flat tails in their own parameter planes. Cluster populations of ages younger and older than 500 Myrs distribute diversely on the disc. The latter has a spatial consistency with the Galactic disc flare. The 3-D spatial comparison between very young clusters ({$<$} 100 Myr) and nearby molecular clouds revealed a wide range of metallicity distribution along the Radcliffe gas cloud wave, indicating a possible inhomogeneous mixing or fast star formation along the wave. This catalogue would serve the community as a useful tool to trace the chemical and dynamical evolution of the Milky Way.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{fujii_sirius_2021, title = {{{SIRIUS Project}}. {{III}}. {{Star-by-star}} Simulations of Star Cluster Formation Using a Direct {{N-body}} Integrator with Stellar Feedback}, author = {Fujii, Michiko S. and Saitoh, Takayuki R. and Hirai, Yutaka and Wang, Long}, year = {2021}, month = mar, journal = {arXiv:2103.02829 [astro-ph]}, eprint = {2103.02829}, primaryclass = {astro-ph}, urldate = {2021-03-08}, abstract = {One of the computational challenges of cluster formation simulations is resolving individual stars and simulating massive clusters with masses of more than \$10\^4 M\_\{\textbackslash odot\}\$ without gravitational softening. Combining direct \$N\$-body code with smoothed-particle hydrodynamics (SPH) code, we have developed a new code, \textbackslash textsc\{ASURA+BRIDGE\}, in which we can integrate stellar particles without softening. We add a feedback model for \textbackslash HII regions into this code, in which thermal and momentum feedback is given within the Str\{\textbackslash "o\}mgren radius. We perform \$N\$-body/SPH simulations of star cluster formation. Without softening, a portion of massive stars are ejected from the forming clusters. As a result, the stellar feedback works outside the clusters. This enhances/suppresses the star formation in initially sub-virial/super-virial clouds. We find that the formed star clusters are denser than currently observed open clusters, but the mass--density relation is consistent with or even higher than that is estimated as an initial cluster density. We also find that some clusters have multiple peaks in their stellar age distribution as a consequence of their hierarchical formation.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2EW6QB9Q\\2103.html}}
@article{fujii_survival_2019, title = {Survival Rates of Planets in Open Clusters: The {{Pleiades}}, {{Hyades}}, and {{Praesepe}} Clusters}, shorttitle = {Survival Rates of Planets in Open Clusters}, author = {Fujii, M. S. and Hori, Y.}, year = {2019}, month = apr, journal = {Astronomy \& Astrophysics}, volume = {624}, pages = {A110}, publisher = {{EDP Sciences}}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201834677}, urldate = {2020-06-24}, abstract = {\emph{Context.{$<$}i/{$>$} In clustered environments, stellar encounters can liberate planets from their host stars via close encounters. Although the detection probability of planets suggests that the planet population in open clusters resembles that in the field, only a few dozen planet-hosting stars have been discovered in open clusters.\emph{Aims.{$<$}i/{$>$} We explore the survival rates of planets against stellar encounters in open clusters similar to the Pleiades, Hyades, and Praesepe and embedded clusters.\emph{Methods.{$<$}i/{$>$} We performed a series of \emph{N{$<$}i/{$>$}-body simulations of high-density and low-density open clusters, open clusters that grow via mergers of subclusters, and embedded clusters. We semi-analytically calculated the survival rate of planets in star clusters up to \textasciitilde 1 Gyr using relative velocities, masses, and impact parameters of intruding stars.\emph{Results.{$<$}i/{$>$} Less than 1.5\% of close-in planets within 1 AU and at most 7\% of planets with 1\textendash 10 AU are ejected by stellar encounters in clustered environments after the dynamical evolution of star clusters. If a planet population from 0.01\textendash 100 AU in an open cluster initially follows the probability distribution function of exoplanets with semi-major axis (\emph{a{$<$}i/{$>$}\textsubscript{p{$<$}sub/{$>$}) between 0.03 and 3 AU in the field discovered by RV surveys ( ), the PDF of surviving planets beyond \textasciitilde 10 AU in open clusters can be slightly modified to . The production rate of free-floating planets (FFPs) per star is 0.0096\textendash 0.18, where we have assumed that all the stars initially have one giant planet with a mass of 1\textendash 13 \emph{M{$<$}i/{$>$}\textsubscript{Jup{$<$}sub/{$>$} in a circular orbit. The expected frequency of FFPs is compatible with the upper limit on that of FFPs indicated by recent microlensing surveys. Our survival rates of planets in open clusters suggest that planets within 10 AU around FGKM-type stars are rich in relatively-young ({$\lessequivlnt$}10\textendash 100 Myr for open clusters and \textasciitilde 1\textendash 10 Myr for embedded clusters), less massive open clusters, which are promising targets for planet searches.}}}}}}}}}}, copyright = {\textcopyright{} ESO 2019}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\S6K6JPJ7\\aa34677-18.html}}
@article{fukushima_star_2020, title = {Star Cluster Formation and Cloud Dispersal by Radiative Feedback: Dependence on Metallicity and Compactness}, shorttitle = {Star Cluster Formation and Cloud Dispersal by Radiative Feedback}, author = {Fukushima, Hajime and Yajima, Hidenobu and Sugimura, Kazuyuki and Hosokawa, Takashi and Omukai, Kazuyuki and Matsumoto, Tomoaki}, year = {2020}, month = may, journal = {arXiv:2005.13401 [astro-ph]}, eprint = {2005.13401}, primaryclass = {astro-ph}, urldate = {2020-05-29}, abstract = {We study star cluster formation in various environments with different metallicities and column densities by performing a suite of three-dimensional radiation hydrodynamics simulations. We find that the photoionization feedback from massive stars controls the star formation efficiency (SFE) in a star-forming cloud, and its impact sensitively depends on the gas metallicity \$Z\$ and initial cloud surface density \$\textbackslash Sigma\$. At \$Z=1\textasciitilde Z\_\{\textbackslash odot\}\$, for instance, the SFE increases from 0.02 to 0.3 with \$\textbackslash Sigma\$ from \$10\$ to \$300\textasciitilde\{\textbackslash rm M\_\{\textbackslash odot\} \{\textbackslash rm pc\^\{-2\}\}\}\$. In low-metallicity cases \$10\^\{-2\}- 10\^\{-1\} Z\_\{\textbackslash odot\}\$, star clusters form from atomic warm gases because the molecule formation time is not short enough with respect to the cooling or dynamical time. In addition, the whole cloud is disrupted more easily by expanding HII bubbles which have higher temperature owing to less efficient cooling. With smaller dust attenuation, the ionizing radiation feedback from nearby massive stars is stronger and terminate star formation in dense clumps. These effects result in inefficient star formation in low-metallicity environments: the SFE is reduced by a factor of \$\textbackslash sim 0.3\$ for the cases with \$Z=10\^\{-2\}\textasciitilde Z\_\{\textbackslash odot\}\$ regardless of \$\textbackslash Sigma\$. Newborn star clusters are also gravitationally less bound. We further develop a new semi-analytical model that can reproduce the simulation results well, particularly the observed dependencies of the SFEs on the cloud surface densities and metallicities.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YDKNQXA7\\2005.html}}
@article{gagne_number_2021, title = {A {{Number}} of {{Nearby Moving Groups}} May Be {{Fragments}} of {{Dissolving Open Clusters}}}, author = {Gagn{\'e}, Jonathan and Faherty, Jacqueline K. and Moranta, Leslie and Popinchalk, Mark}, year = {2021}, month = jun, journal = {arXiv:2106.11873 [astro-ph]}, eprint = {2106.11873}, primaryclass = {astro-ph}, urldate = {2021-06-24}, abstract = {We propose that fourteen co-moving groups of stars uncovered by Kounkel \& Covey (2019) may be related to known nearby moving groups and bridge those and nearby open clusters with similar ages and space velocities. This indicates that known nearby moving groups may be spatially much more extended than previously though, and some of them might be parts of tidal tails around the cores of known open clusters, reminiscent of those recently found around the Hyades and a handful of other nearby clusters. For example, we find that both the nearby Carina and Columba associations may be linked to Theia 208 from Kounkel \& Covey (2019) and together form parts of a large tidal tail around the Platais 8 open cluster. The AB Doradus moving group and Theia 301 may form a trailing tidal tail behind the Pleiades open cluster, with hints of a possible leading tidal tail in Theia 369. We similarly find that IC 2391 and its tidal tails identified by Meingast et al. (2021) may be extended by the nearby Argus association and are possibly further extended by Theia 115. The nearby Octans and Octans-Near associations, as well as Theia 94 and 95, may form a large tidal tail leading the poorly studied Platais 5 open cluster candidate. While a preliminary analysis of Gaia color-magnitude sequences hint that these structures are plausibly related, more observational evidence is still required to corroborate their consistent ages and space velocities. These observations may change our current understanding of nearby moving groups and the different pathways through which they can form. While some moving groups may have formed loosely in extended star-formation events with rich spatial structure, others may in fact correspond to the tidal tails of nearby open clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
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I. and Ziaeepour, H. and Zschocke, S.}, year = {2016}, month = nov, journal = {Astronomy \& Astrophysics}, volume = {595}, pages = {A1}, issn = {0004-6361}, doi = {10.1051/0004-6361/201629272}, urldate = {2022-03-25}, abstract = {Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page. {$<$}P /{$><$}A href="http://www.cosmos.esa.int/gaia"{$>$}http://www.cosmos.esa.int/gaia{$<$}/A{$>$}}, langid = {english}}
@article{gaia_collaboration_gaia_2021, title = {Gaia {{Early Data Release}} 3: {{Summary}} of the Contents and Survey Properties}, shorttitle = {Gaia {{Early Data Release}} 3}, author = {{Gaia Collaboration} and Brown, A. G. A. and Vallenari, A. and Prusti, T. and {de Bruijne}, J. H. J. and Babusiaux, C. and Biermann, M.}, year = {2021}, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2012.01533}, pages = {A1}, urldate = {2021-01-04}, abstract = {We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G\_BP-G\_RP) colour are also available. The passbands for G, G\_BP, and G\_RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 percent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30--40 percent for the parallaxes and by a factor \textasciitilde 2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G\_BP, and G\_RP is valid over the entire magnitude and colour range, with no systematics above the 1 percent level.}, archiveprefix = {arxiv}, keywords = {\_tablet\_modified,Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CVVYIU2K\\Gaia Collaboration et al_2020_Gaia Early Data Release 3.pdf;C\:\\Users\\Emily\\Zotero\\storage\\K2BGI6UM\\2012.html}}
@article{gaia_collaboration_gaia_2022, title = {Gaia {{Data Release}} 3. {{Summary}} of the Content and Survey Properties}, author = {{Gaia Collaboration} and Vallenari, A. and Brown, A.G.A. and Prusti, T. and {et al.}}, year = {2022}, month = jun, journal = {arXiv e-prints}, volume = {arXiv:2208.00211}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202243940}, urldate = {2023-01-19}, abstract = {Methods. The Gaia DR3 catalogue is the outcome of the processing of raw data collected with the Gaia instruments during the first 34 months of the mission by the Gaia Data Processing and Analysis Consortium. Results. The Gaia DR3 catalogue contains the same source list, celestial positions, proper motions, parallaxes, and broad band photometry in the G, GBP, and GRP pass-bands already present in the Early Third Data Release, Gaia EDR3. Gaia DR3 introduces an impressive wealth of new data products. More than 33 million objects in the ranges GRVS {$<$} 14 and 3100 {$<$} Teff {$<$} 14500, have new determinations of their mean radial velocities based on data collected by Gaia. We provide GRVS magnitudes for most sources with radial velocities, and a line broadening parameter is listed for a subset of these. Mean Gaia spectra are made available to the community. The Gaia DR3 catalogue includes about 1 million mean spectra from the radial velocity spectrometer, and about 220 million low-resolution blue and red prism photometer BP/RP mean spectra. The results of the analysis of epoch photometry are provided for some 10 million sources across 24 variability types. Gaia DR3 includes astrophysical parameters and source class probabilities for about 470 million and 1500 million sources, respectively, including stars, galaxies, and quasars. Orbital elements and trend parameters are provided for some 800 000 astrometric, spectroscopic and eclipsing binaries. More than 150 000 Solar System objects, including new discoveries, with preliminary orbital solutions and individual epoch observations are part of this release. Reflectance spectra derived from the epoch BP/RP spectral data are published for about 60 000 asteroids. Finally, an additional data set is provided, namely the Gaia Andromeda Photometric Survey, consisting of the photometric time series for all sources located in a 5.5 degree radius field centred on the Andromeda galaxy. Conclusions. This data release represents a major advance with respect to Gaia DR2 and Gaia EDR3 because of the unprecedented quantity, quality, and variety of source astrophysical data. To date this is the largest collection of all-sky spectrophotometry, radial velocities, variables, and astrophysical parameters derived from both low- and high-resolution spectra and includes a spectrophotometric and dynamical survey of SSOs of the highest accuracy. The non-single star content surpasses the existing data by orders of magnitude. The quasar host and galaxy light profile collection is the first such survey that is all sky and space based. The astrophysical information provided in Gaia DR3 will unleash the full potential of Gaia's exquisite astrometric, photometric, and radial velocity surveys.}, langid = {english}}
@article{gaiacollaboration_gaia_data_2016, title = {Gaia {{Data Release}} 1. {{Summary}} of the Astrometric, Photometric, and Survey Properties}, author = {{Gaia Collaboration} and Brown, A. G. A. and Vallenari, A. and Prusti, T. and {de Bruijne}, J. H. J. and Mignard, F. and Drimmel, R. and Babusiaux, C. and {Bailer-Jones}, C. A. L. and Bastian, U. and Biermann, M. and Evans, D. W. and Eyer, L. and Jansen, F. and Jordi, C. and Katz, D. and Klioner, S. A. and Lammers, U. and Lindegren, L. and Luri, X. and O'Mullane, W. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and Valette, V. and {van Leeuwen}, F. and Walton, N. A. and Aerts, C. and Arenou, F. and Cropper, M. and H{\o}g, E. and Lattanzi, M. G. and Grebel, E. K. and Holland, A. D. and Huc, C. and Passot, X. and Perryman, M. and Bramante, L. and Cacciari, C. and Casta{\~n}eda, J. and Chaoul, L. and Cheek, N. and De Angeli, F. and Fabricius, C. and Guerra, R. and Hern{\'a}ndez, J. and {Jean-Antoine-Piccolo}, A. and Masana, E. and Messineo, R. and Mowlavi, N. and Nienartowicz, K. and {Ord{\'o}{\~n}ez-Blanco}, D. and Panuzzo, P. and Portell, J. and Richards, P. J. and Riello, M. and Seabroke, G. M. and Tanga, P. and Th{\'e}venin, F. and Torra, J. and Els, S. G. and {Gracia-Abril}, G. and Comoretto, G. and {Garcia-Reinaldos}, M. and Lock, T. and Mercier, E. and Altmann, M. and Andrae, R. and Astraatmadja, T. L. and {Bellas-Velidis}, I. and Benson, K. and Berthier, J. and Blomme, R. and Busso, G. and Carry, B. and Cellino, A. and Clementini, G. and Cowell, S. and Creevey, O. and Cuypers, J. and Davidson, M. and De Ridder, J. and {de Torres}, A. and Delchambre, L. and Dell'Oro, A. and Ducourant, C. and Fr{\'e}mat, Y. and {Garc{\'i}a-Torres}, M. and Gosset, E. and Halbwachs, J. -L. and Hambly, N. C. and Harrison, D. L. and Hauser, M. and Hestroffer, D. and Hodgkin, S. T. and Huckle, H. E. and Hutton, A. and Jasniewicz, G. and Jordan, S. and Kontizas, M. and Korn, A. J. and Lanzafame, A. C. and Manteiga, M. and Moitinho, A. and Muinonen, K. and Osinde, J. and Pancino, E. and Pauwels, T. and Petit, J. -M. and {Recio-Blanco}, A. and Robin, A. C. and Sarro, L. M. and Siopis, C. and Smith, M. and Smith, K. W. and Sozzetti, A. and Thuillot, W. and {van Reeven}, W. and Viala, Y. and Abbas, U. and Abreu Aramburu, A. and Accart, S. and Aguado, J. J. and Allan, P. M. and Allasia, W. and Altavilla, G. and {\'A}lvarez, M. A. and Alves, J. and Anderson, R. I. and Andrei, A. H. and Anglada Varela, E. and Antiche, E. and Antoja, T. and Ant{\'o}n, S. and Arcay, B. and Bach, N. and Baker, S. G. and {Balaguer-N{\'u}{\~n}ez}, L. and Barache, C. and Barata, C. and Barbier, A. and Barblan, F. and {Barrado y Navascu{\'e}s}, D. and Barros, M. and Barstow, M. A. and Becciani, U. and Bellazzini, M. and Bello Garc{\'i}a, A. and Belokurov, V. and Bendjoya, P. and Berihuete, A. and Bianchi, L. and Bienaym{\'e}, O. and Billebaud, F. and Blagorodnova, N. and {Blanco-Cuaresma}, S. and Boch, T. and Bombrun, A. and Borrachero, R. and Bouquillon, S. and Bourda, G. and Bouy, H. and Bragaglia, A. and Breddels, M. A. and Brouillet, N. and Br{\"u}semeister, T. and Bucciarelli, B. and Burgess, P. and Burgon, R. and Burlacu, A. and Busonero, D. and Buzzi, R. and Caffau, E. and Cambras, J. and Campbell, H. and Cancelliere, R. and {Cantat-Gaudin}, T. and Carlucci, T. and Carrasco, J. M. and Castellani, M. and Charlot, P. and Charnas, J. and Chiavassa, A. and Clotet, M. and Cocozza, G. and Collins, R. S. and Costigan, G. and Crifo, F. and Cross, N. J. G. and Crosta, M. and Crowley, C. and Dafonte, C. and Damerdji, Y. and Dapergolas, A. and David, P. and David, M. and De Cat, P. and {de Felice}, F. and {de Laverny}, P. and De Luise, F. and De March, R. and {de Martino}, D. and {de Souza}, R. and Debosscher, J. and {del Pozo}, E. and Delbo, M. and Delgado, A. and Delgado, H. E. and Di Matteo, P. and Diakite, S. and Distefano, E. and Dolding, C. and Dos Anjos, S. and Drazinos, P. and Duran, J. and Dzigan, Y. and Edvardsson, B. and Enke, H. and Evans, N. W. and Eynard Bontemps, G. and Fabre, C. and Fabrizio, M. and Faigler, S. and Falc{\~a}o, A. J. and Farr{\`a}s Casas, M. and Federici, L. and Fedorets, G. and {Fern{\'a}ndez-Hern{\'a}ndez}, J. and Fernique, P. and Fienga, A. and Figueras, F. and Filippi, F. and Findeisen, K. and Fonti, A. and Fouesneau, M. and Fraile, E. and Fraser, M. and Fuchs, J. and Gai, M. and Galleti, S. and Galluccio, L. and Garabato, D. and {Garc{\'i}a-Sedano}, F. and Garofalo, A. and Garralda, N. and Gavras, P. and Gerssen, J. and Geyer, R. and Gilmore, G. and Girona, S. and Giuffrida, G. and Gomes, M. and {Gonz{\'a}lez-Marcos}, A. and {Gonz{\'a}lez-N{\'u}{\~n}ez}, J. and {Gonz{\'a}lez-Vidal}, J. J. and Granvik, M. and Guerrier, A. and Guillout, P. and Guiraud, J. and G{\'u}rpide, A. and {Guti{\'e}rrez-S{\'a}nchez}, R. and Guy, L. P. and Haigron, R. and Hatzidimitriou, D. and Haywood, M. and Heiter, U. and Helmi, A. and Hobbs, D. and Hofmann, W. and Holl, B. and Holland, G. and Hunt, J. A. S. and Hypki, A. and Icardi, V. and Irwin, M. and {Jevardat de Fombelle}, G. and Jofr{\'e}, P. and Jonker, P. G. and Jorissen, A. and Julbe, F. and Karampelas, A. and Kochoska, A. and Kohley, R. and Kolenberg, K. and Kontizas, E. and Koposov, S. E. and Kordopatis, G. and Koubsky, P. and {Krone-Martins}, A. and Kudryashova, M. and Kull, I. and Bachchan, R. K. and {Lacoste-Seris}, F. and Lanza, A. F. and Lavigne, J. -B. and {Le Poncin-Lafitte}, C. and Lebreton, Y. and Lebzelter, T. and Leccia, S. and Leclerc, N. and {Lecoeur-Taibi}, I. and Lemaitre, V. and Lenhardt, H. and Leroux, F. and Liao, S. and Licata, E. and Lindstr{\o}m, H. E. P. and Lister, T. A. and Livanou, E. and Lobel, A. and L{\"o}ffler, W. and L{\'o}pez, M. and Lorenz, D. and MacDonald, I. and Magalh{\~a}es Fernandes, T. and Managau, S. and Mann, R. G. and Mantelet, G. and Marchal, O. and Marchant, J. M. and Marconi, M. and Marinoni, S. and Marrese, P. M. and Marschalk{\'o}, G. and Marshall, D. J. and {Mart{\'i}n-Fleitas}, J. M. and Martino, M. and Mary, N. and Matijevi{\v c}, G. and Mazeh, T. and McMillan, P. J. and Messina, S. and Michalik, D. and Millar, N. R. and Miranda, B. M. H. and Molina, D. and Molinaro, R. and Molinaro, M. and Moln{\'a}r, L. and Moniez, M. and Montegriffo, P. and Mor, R. and Mora, A. and Morbidelli, R. and Morel, T. and Morgenthaler, S. and Morris, D. and Mulone, A. F. and Muraveva, T. and Musella, I. and Narbonne, J. and Nelemans, G. and Nicastro, L. and Noval, L. and Ord{\'e}novic, C. and {Ordieres-Mer{\'e}}, J. and Osborne, P. and Pagani, C. and Pagano, I. and Pailler, F. and Palacin, H. and Palaversa, L. and Parsons, P. and Pecoraro, M. and Pedrosa, R. and Pentik{\"a}inen, H. and Pichon, B. and Piersimoni, A. M. and Pineau, F. -X. and Plachy, E. and Plum, G. and Poujoulet, E. and Pr{\v s}a, A. and Pulone, L. and Ragaini, S. and Rago, S. and Rambaux, N. and {Ramos-Lerate}, M. and Ranalli, P. and Rauw, G. and Read, A. and Regibo, S. and Reyl{\'e}, C. and Ribeiro, R. A. and Rimoldini, L. and Ripepi, V. and Riva, A. and Rixon, G. and Roelens, M. and {Romero-G{\'o}mez}, M. and Rowell, N. and Royer, F. and {Ruiz-Dern}, L. and Sadowski, G. and Sagrist{\`a} Sell{\'e}s, T. and Sahlmann, J. and Salgado, J. and Salguero, E. and Sarasso, M. and Savietto, H. and Schultheis, M. and Sciacca, E. and Segol, M. and Segovia, J. C. and Segransan, D. and Shih, I. -C. and Smareglia, R. and Smart, R. L. and Solano, E. and Solitro, F. and Sordo, R. and Soria Nieto, S. and Souchay, J. and Spagna, A. and Spoto, F. and Stampa, U. and Steele, I. A. and Steidelm{\"u}ller, H. and Stephenson, C. A. and Stoev, H. and Suess, F. 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T. and Delle Luche, C. and Domingues, C. D. and Dubath, P. and Fodor, F. and Fr{\'e}zouls, B. and Fries, A. and Fustes, D. and Fyfe, D. and Gallardo, E. and Gallegos, J. and Gardiol, D. and Gebran, M. and Gomboc, A. and G{\'o}mez, A. and Grux, E. and Gueguen, A. and Heyrovsky, A. and Hoar, J. and Iannicola, G. and Isasi Parache, Y. and Janotto, A. -M. and Joliet, E. and Jonckheere, A. and Keil, R. and Kim, D. -W. and Klagyivik, P. and Klar, J. and Knude, J. and Kochukhov, O. and Kolka, I. and Kos, J. and Kutka, A. and Lainey, V. and LeBouquin, D. and Liu, C. and Loreggia, D. and Makarov, V. V. and Marseille, M. G. and Martayan, C. and {Martinez-Rubi}, O. and Massart, B. and Meynadier, F. and Mignot, S. and Munari, U. and Nguyen, A. -T. and Nordlander, T. and Ocvirk, P. and O'Flaherty, K. S. and Olias Sanz, A. and Ortiz, P. and Osorio, J. and Oszkiewicz, D. and Ouzounis, A. and Palmer, M. and Park, P. and Pasquato, E. and Peltzer, C. and Peralta, J. and P{\'e}turaud, F. and Pieniluoma, T. and Pigozzi, E. and Poels, J. and Prat, G. and Prod'homme, T. and Raison, F. and Rebordao, J. M. and Risquez, D. and {Rocca-Volmerange}, B. and Rosen, S. and {Ruiz-Fuertes}, M. I. and Russo, F. and Sembay, S. and Serraller Vizcaino, I. and Short, A. and Siebert, A. and Silva, H. and Sinachopoulos, D. and Slezak, E. and Soffel, M. and Sosnowska, D. and Strai{\v z}ys, V. and {ter Linden}, M. and Terrell, D. and Theil, S. and Tiede, C. and Troisi, L. and Tsalmantza, P. and Tur, D. and Vaccari, M. and Vachier, F. and Valles, P. and Van Hamme, W. and Veltz, L. and Virtanen, J. and Wallut, J. -M. and Wichmann, R. and Wilkinson, M. I. and Ziaeepour, H. and Zschocke, S.}, year = {2016}, month = nov, journal = {Astronomy and Astrophysics}, volume = {595}, pages = {A2}, issn = {0004-6361}, doi = {10.1051/0004-6361/201629512}, urldate = {2023-04-06}, abstract = {Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims: A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods: The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results: Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the Hipparcos and Tycho-2 catalogues - a realisation of the Tycho-Gaia Astrometric Solution (TGAS) - and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of 3000 Cepheid and RR Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr-1 for the proper motions. A systematic component of 0.3 mas should be added to the parallax uncertainties. For the subset of 94 000 Hipparcos stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr-1. For the secondary astrometric data set, the typical uncertainty of the positions is 10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to 0.03 mag over the magnitude range 5 to 20.7. Conclusions: Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data.}, keywords = {astrometry,Astrophysics - Instrumentation and Methods for Astrophysics,catalogs,parallaxes,proper motions,surveys}, annotation = {ADS Bibcode: 2016A\&A...595A...2G}}
@article{gaiacollaboration_gaia_data_2017, title = {Gaia {{Data Release}} 1. {{Open}} Cluster Astrometry: Performance, Limitations, and Future Prospects}, author = {{Gaia Collaboration} and {van Leeuwen}, F. and Vallenari, A. and Jordi, C. and Lindegren, L. and Bastian, U. and Prusti, T. and {de Bruijne}, J. H. J. and Brown, A. G. A. and Babusiaux, C. and {Bailer-Jones}, C. A. L. and Biermann, M. and Evans, D. W. and Eyer, L. and Jansen, F. and Klioner, S. A. and Lammers, U. and Luri, X. and Mignard, F. and Panem, C. and Pourbaix, D. and Randich, S. and Sartoretti, P. and Siddiqui, H. I. and Soubiran, C. and Valette, V. and Walton, N. A. and Aerts, C. and Arenou, F. and Cropper, M. and Drimmel, R. and H{\o}g, E. and Katz, D. and Lattanzi, M. G. and O'Mullane, W. and Grebel, E. K. and Holland, A. D. and Huc, C. and Passot, X. and Perryman, M. and Bramante, L. and Cacciari, C. and Casta{\~n}eda, J. and Chaoul, L. and Cheek, N. and De Angeli, F. and Fabricius, C. and Guerra, R. and Hern{\'a}ndez, J. and {Jean-Antoine-Piccolo}, A. and Masana, E. and Messineo, R. and Mowlavi, N. and Nienartowicz, K. and {Ord{\'o}{\~n}ez-Blanco}, D. and Panuzzo, P. and Portell, J. and Richards, P. J. and Riello, M. and Seabroke, G. M. and Tanga, P. and Th{\'e}venin, F. and Torra, J. and Els, S. G. and {Gracia-Abril}, G. and Comoretto, G. and {Garcia-Reinaldos}, M. and Lock, T. and Mercier, E. and Altmann, M. and Andrae, R. and Astraatmadja, T. L. and {Bellas-Velidis}, I. and Benson, K. and Berthier, J. and Blomme, R. and Busso, G. and Carry, B. and Cellino, A. and Clementini, G. and Cowell, S. and Creevey, O. and Cuypers, J. and Davidson, M. and De Ridder, J. and {de Torres}, A. and Delchambre, L. and Dell'Oro, A. and Ducourant, C. and Fr{\'e}mat, Y. and {Garc{\'i}a-Torres}, M. and Gosset, E. and Halbwachs, J. -L. and Hambly, N. C. and Harrison, D. L. and Hauser, M. and Hestroffer, D. and Hodgkin, S. T. and Huckle, H. E. and Hutton, A. and Jasniewicz, G. and Jordan, S. and Kontizas, M. and Korn, A. J. and Lanzafame, A. C. and Manteiga, M. and Moitinho, A. and Muinonen, K. and Osinde, J. and Pancino, E. and Pauwels, T. and Petit, J. -M. and {Recio-Blanco}, A. and Robin, A. C. and Sarro, L. M. and Siopis, C. and Smith, M. and Smith, K. W. and Sozzetti, A. and Thuillot, W. and {van Reeven}, W. and Viala, Y. and Abbas, U. and Abreu Aramburu, A. and Accart, S. and Aguado, J. J. and Allan, P. M. and Allasia, W. and Altavilla, G. and {\'A}lvarez, M. A. and Alves, J. and Anderson, R. I. and Andrei, A. H. and Anglada Varela, E. and Antiche, E. and Antoja, T. and Ant{\'o}n, S. and Arcay, B. and Bach, N. and Baker, S. G. and {Balaguer-N{\'u}{\~n}ez}, L. and Barache, C. and Barata, C. and Barbier, A. and Barblan, F. and {Barrado y Navascu{\'e}s}, D. and Barros, M. and Barstow, M. A. and Becciani, U. and Bellazzini, M. and Bello Garc{\'i}a, A. and Belokurov, V. and Bendjoya, P. and Berihuete, A. and Bianchi, L. and Bienaym{\'e}, O. and Billebaud, F. and Blagorodnova, N. and {Blanco-Cuaresma}, S. and Boch, T. and Bombrun, A. and Borrachero, R. and Bouquillon, S. and Bourda, G. and Bouy, H. and Bragaglia, A. and Breddels, M. 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J. and {Mart{\'i}n-Fleitas}, J. M. and Martino, M. and Mary, N. and Matijevi{\v c}, G. and Mazeh, T. and McMillan, P. J. and Messina, S. and Michalik, D. and Millar, N. R. and Miranda, B. M. H. and Molina, D. and Molinaro, R. and Molinaro, M. and Moln{\'a}r, L. and Moniez, M. and Montegriffo, P. and Mor, R. and Mora, A. and Morbidelli, R. and Morel, T. and Morgenthaler, S. and Morris, D. and Mulone, A. F. and Muraveva, T. and Musella, I. and Narbonne, J. and Nelemans, G. and Nicastro, L. and Noval, L. and Ord{\'e}novic, C. and {Ordieres-Mer{\'e}}, J. and Osborne, P. and Pagani, C. and Pagano, I. and Pailler, F. and Palacin, H. and Palaversa, L. and Parsons, P. and Pecoraro, M. and Pedrosa, R. and Pentik{\"a}inen, H. and Pichon, B. and Piersimoni, A. M. and Pineau, F. -X. and Plachy, E. and Plum, G. and Poujoulet, E. and Pr{\v s}a, A. and Pulone, L. and Ragaini, S. and Rago, S. and Rambaux, N. and {Ramos-Lerate}, M. and Ranalli, P. and Rauw, G. and Read, A. and Regibo, S. and Reyl{\'e}, C. and Ribeiro, R. A. and Rimoldini, L. and Ripepi, V. and Riva, A. and Rixon, G. and Roelens, M. and {Romero-G{\'o}mez}, M. and Rowell, N. and Royer, F. and {Ruiz-Dern}, L. and Sadowski, G. and Sagrist{\`a} Sell{\'e}s, T. and Sahlmann, J. and Salgado, J. and Salguero, E. and Sarasso, M. and Savietto, H. and Schultheis, M. and Sciacca, E. and Segol, M. and Segovia, J. C. and Segransan, D. and Shih, I. -C. and Smareglia, R. and Smart, R. L. and Solano, E. and Solitro, F. and Sordo, R. and Soria Nieto, S. and Souchay, J. and Spagna, A. and Spoto, F. and Stampa, U. and Steele, I. A. and Steidelm{\"u}ller, H. and Stephenson, C. A. and Stoev, H. and Suess, F. F. and S{\"u}veges, M. and Surdej, J. and Szabados, L. and {Szegedi-Elek}, E. and Tapiador, D. and Taris, F. and Tauran, G. and Taylor, M. B. and Teixeira, R. and Terrett, D. and Tingley, B. and Trager, S. C. and Turon, C. and Ulla, A. and Utrilla, E. and Valentini, G. and {van Elteren}, A. and Van Hemelryck, E. and {vanLeeuwen}, M. and Varadi, M. and Vecchiato, A. and Veljanoski, J. and Via, T. and Vicente, D. and Vogt, S. and Voss, H. and Votruba, V. and Voutsinas, S. and Walmsley, G. and Weiler, M. and Weingrill, K. and Wevers, T. and Wyrzykowski, {\L}. and Yoldas, A. and {\v Z}erjal, M. and Zucker, S. and Zurbach, C. and Zwitter, T. and Alecu, A. and Allen, M. and Allende Prieto, C. and Amorim, A. and {Anglada-Escud{\'e}}, G. and Arsenijevic, V. and Azaz, S. and Balm, P. and Beck, M. and Bernstein, H. -H. and Bigot, L. and Bijaoui, A. and Blasco, C. and Bonfigli, M. and Bono, G. and Boudreault, S. and Bressan, A. and Brown, S. and Brunet, P. -M. and Bunclark, P. and Buonanno, R. and Butkevich, A. G. and Carret, C. and Carrion, C. and Chemin, L. and Ch{\'e}reau, F. and Corcione, L. and Darmigny, E. and {de Boer}, K. S. and {de Teodoro}, P. and {de Zeeuw}, P. T. and Delle Luche, C. and Domingues, C. D. and Dubath, P. and Fodor, F. and Fr{\'e}zouls, B. and Fries, A. and Fustes, D. and Fyfe, D. and Gallardo, E. and Gallegos, J. and Gardiol, D. and Gebran, M. and Gomboc, A. and G{\'o}mez, A. and Grux, E. and Gueguen, A. and Heyrovsky, A. and Hoar, J. and Iannicola, G. and Isasi Parache, Y. and Janotto, A. -M. and Joliet, E. and Jonckheere, A. and Keil, R. and Kim, D. -W. and Klagyivik, P. and Klar, J. and Knude, J. and Kochukhov, O. and Kolka, I. and Kos, J. and Kutka, A. and Lainey, V. and LeBouquin, D. and Liu, C. and Loreggia, D. and Makarov, V. V. and Marseille, M. G. and Martayan, C. and {Martinez-Rubi}, O. and Massart, B. and Meynadier, F. and Mignot, S. and Munari, U. and Nguyen, A. -T. and Nordlander, T. and O'Flaherty, K. S. and Ocvirk, P. and Olias Sanz, A. and Ortiz, P. and Osorio, J. and Oszkiewicz, D. and Ouzounis, A. and Palmer, M. and Park, P. and Pasquato, E. and Peltzer, C. and Peralta, J. and P{\'e}turaud, F. and Pieniluoma, T. and Pigozzi, E. and Poels, J. and Prat, G. and Prod'homme, T. and Raison, F. and Rebordao, J. M. and Risquez, D. and {Rocca-Volmerange}, B. and Rosen, S. and {Ruiz-Fuertes}, M. I. and Russo, F. and Sembay, S. and Serraller Vizcaino, I. and Short, A. and Siebert, A. and Silva, H. and Sinachopoulos, D. and Slezak, E. and Soffel, M. and Sosnowska, D. and Strai{\v z}ys, V. and {ter Linden}, M. and Terrell, D. and Theil, S. and Tiede, C. and Troisi, L. and Tsalmantza, P. and Tur, D. and Vaccari, M. and Vachier, F. and Valles, P. and Van Hamme, W. and Veltz, L. and Virtanen, J. and Wallut, J. -M. and Wichmann, R. and Wilkinson, M. I. and Ziaeepour, H. and Zschocke, S.}, year = {2017}, month = may, journal = {Astronomy \& Astrophysics}, volume = {601}, eprint = {1703.01131}, primaryclass = {astro-ph.SR}, pages = {A19}, doi = {10.1051/0004-6361/201730552}, archiveprefix = {arxiv}, keywords = {astrometry,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general}}
@article{gal_dropout_2015-1, title = {Dropout as a {{Bayesian Approximation}}: {{Representing Model Uncertainty}} in {{Deep Learning}}}, author = {Gal, Yarin and Ghahramani, Zoubin}, year = {2015}, month = jun, journal = {arXiv e-prints}, pages = {arXiv:1506.02142}, doi = {10.48550/arXiv.1506.02142}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{gal_dropout_2016, title = {Dropout as a {{Bayesian Approximation}}: {{Representing Model Uncertainty}} in {{Deep Learning}}}, shorttitle = {Dropout as a {{Bayesian Approximation}}}, author = {Gal, Yarin and Ghahramani, Zoubin}, year = {2016}, month = oct, journal = {arXiv:1506.02142 [cs, stat]}, eprint = {1506.02142}, primaryclass = {cs, stat}, urldate = {2022-03-31}, abstract = {Deep learning tools have gained tremendous attention in applied machine learning. However such tools for regression and classification do not capture model uncertainty. In comparison, Bayesian models offer a mathematically grounded framework to reason about model uncertainty, but usually come with a prohibitive computational cost. In this paper we develop a new theoretical framework casting dropout training in deep neural networks (NNs) as approximate Bayesian inference in deep Gaussian processes. A direct result of this theory gives us tools to model uncertainty with dropout NNs -- extracting information from existing models that has been thrown away so far. This mitigates the problem of representing uncertainty in deep learning without sacrificing either computational complexity or test accuracy. We perform an extensive study of the properties of dropout's uncertainty. Various network architectures and non-linearities are assessed on tasks of regression and classification, using MNIST as an example. We show a considerable improvement in predictive log-likelihood and RMSE compared to existing state-of-the-art methods, and finish by using dropout's uncertainty in deep reinforcement learning.}, archiveprefix = {arxiv}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{garro_inspection_2021, title = {Inspection of 19 Globular Cluster Candidates in the {{Galactic}} Bulge with the {{VVV}} Survey}, author = {Garro, E. R. and Minniti, D. and G{\'o}mez, M. and {Alonso-Garc{\'i}a}, J. and Ripepi, V. and {Fern{\'a}ndez-Trincado}, J. G. and C{\'a}diz, F. Vivanco}, year = {2021}, month = nov, journal = {arXiv:2111.08317 [astro-ph]}, eprint = {2111.08317}, primaryclass = {astro-ph}, urldate = {2021-11-23}, abstract = {The census of the globular clusters (GCs) in the Milky Way (MW) is still a work in progress. We explore the nature of 19 new GC candidates in the Galactic bulge, based on the analysis of their colour-magnitude diagrams (CMDs) in the near-IR, using the VISTA Variables in the Via L\textbackslash 'actea Survey (VVV) database. We estimate their main astrophysical parameters: reddening and extinction, distance, total luminosity, mean cluster proper motions (PMs), metallicity and age. We obtain the cluster catalogues including the likely cluster members by applying a decontamination procedure on the observed CMDs, based upon the vector PM diagrams from VIRAC2. We estimate a wide reddening range of the \$0.25 \textbackslash leqslant E(J-K\_s) \textbackslash leqslant 2.0\$ mag and extinction \$0.11 \textbackslash leqslant A\_\{Ks\} \textbackslash leqslant 0.86\$ mag for the sample clusters as expected in the bulge regions. The range of heliocentric distances is \$6.8\textbackslash leqslant D\textbackslash leqslant 11.4\$ kpc. This allows us to place these clusters between 0.56 and 3.25 kpc from the Galactic centre, assuming \$R\_\{\textbackslash odot\}=8.2\$ kpc. Also, their PMs are kinematically similar to the typical motion of the Galactic bulge, apart from VVV-CL160, which shows different PMs. We also derive their metallicities and ages, finding \$-1.40 \textbackslash leqslant\$ [Fe/H] \$\textbackslash leqslant 0.0\$ dex and \$t\textbackslash approx 8-13\$ Gyr respectively. The luminosities are calculated both in \$K\_\{s\}-\$ and V-bands, recovering \$-3.4 \textbackslash leqslant M\_V \textbackslash leqslant -7.5\$. We also examine the possible RR Lyrae members found in the cluster fields. Based on their positions, kinematics, metallicities and ages and comparing our results with the literature, we conclude that 9 candidates are real GCs, 7 need more observations to be fully confirmed as GCs, whereas 3 candidates are discarded for being younger open clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\UHZ446KR\\2111.html}}
@article{garro_unveiling_2021, title = {Unveiling the Nature of 12 New Low-Luminosity {{Galactic Globular Cluster Candidates}}}, author = {Garro, E. R. and Minniti, D. and Alessi, B. and Patchick, D. and Kronberger, M. and {Alonso-Garc{\'i}a}, J. and {Fern{\'a}ndez-Trincado}, J. G. and G{\'o}mez, M. and Hempel, M. and Pullen, J. B. and Saito, R. K. and Ripepi, V. and Bacigalupo, R. Zelada}, year = {2021}, month = dec, journal = {arXiv:2112.13591 [astro-ph]}, eprint = {2112.13591}, primaryclass = {astro-ph}, urldate = {2022-01-11}, abstract = {The Galactic globular cluster system is incomplete, especially in the low latitude regions of the Galactic bulge and disk. We report the physical characterization of twelve star clusters in the Milky Way, most of which are explored here for the first time. Our aim is determining their main physical parameters, such as reddening and extinction, metallicity, age, total luminosity, mean cluster proper motions (PMs), distances, in order to unveil their physical nature. We study the clusters using optical and near-infrared (NIR) datasets. We use the Gaia Early Data Release 3 (EDR3) PMs in order to perform a PM-decontamination procedure and build final catalogues. We match the Gaia EDR3 with the VISTA Variables in the V\textbackslash 'ia L\textbackslash 'actea extended (VVVX) survey and Two Micron All Sky survey (2MASS) in the NIR, in order to construct complete colour-magnitude diagrams (CMDs) and investigate the clusters properties. The extinctions are evaluated using existing reddening maps, spanning \$0.09\textbackslash lesssim A\_\{Ks\}\textbackslash lesssim 0.86\$ mag and \$0.89 \textbackslash lesssim A\_\{G\}\textbackslash lesssim 4.72\$ mag in the NIR and optical, respectively. We obtain their heliocentric distances, that range from about 4 to 20 kpc, placing these clusters at \$3\textbackslash lesssim R\_\{G\}\textbackslash lesssim 14\$ kpc from the Galactic centre. The best PARSEC isochrone fit yields a metallicity range of \$-1.8{$<\$$}[Fe/H]\${$<$}+0.3\$ and an approximative age range of \$2{$<\$$}Age\${$<$}14\$ Gyr. We find that all clusters have low-luminosities, with \$-6.9}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CP3V8MLW\\2112.html}}
@article{gatto_search_2020, title = {A Search for Star Clusters in the Outskirts of the {{Large Magellanic Cloud}}: Indication of Clusters in the Age Gap}, shorttitle = {A Search for Star Clusters in the Outskirts of the {{Large Magellanic Cloud}}}, author = {Gatto, M. and Ripepi, V. and Bellazzini, M. and Cignoni, M. and Cioni, M.-R. L. and Dall'Ora, M. and Longo, G. and Marconi, M. and Schipani, P. and Tosi, M.}, year = {2020}, month = jul, journal = {arXiv:2007.00341 [astro-ph]}, eprint = {2007.00341}, primaryclass = {astro-ph}, urldate = {2020-07-02}, abstract = {The YMCA (\{\textbackslash it Yes, Magellanic Clouds Again\}) and STEP (\{\textbackslash it The SMC in Time: Evolution of a Prototype interacting late-type dwarf galaxy\}) projects are deep \$g\$,\$i\$ photometric surveys carried out with the VLT Survey Telescope (VST) and devoted to study the outskirts of the Magellanic System. A main goal of YMCA and STEP is to identify candidate stellar clusters and complete their census out to the outermost regions of the Magellanic Clouds. We adopted a specific over-density search technique coupled with a visual inspection of the color magnitude diagrams (CMDs) to select the best candidates and estimate their ages. To date, we analysed a region of 23 sq. deg. in the outskirts of the Large Magellanic Cloud, detecting 85 bona-fide cluster candidates, 16 of which have estimated ages falling in the so called "age gap". We use these objects together with literature data to gain insight into the formation and interaction history of the Magellanic Clouds.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{gieles_velocity_2010, title = {On the Velocity Dispersion of Young Star Clusters: Super-Virial or Binaries?}, shorttitle = {On the Velocity Dispersion of Young Star Clusters}, author = {Gieles, M. and Sana, H. and Portegies Zwart, S. F.}, year = {2010}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {402}, pages = {1750--1757}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2009.15993.x}, urldate = {2022-03-24}, abstract = {Many young extra-galactic clusters have a measured velocity dispersion that is too high for the mass derived from their age and total luminosity, which has led to the suggestion that they are not in virial equilibrium. Most of these clusters are confined to a narrow age range centred around 10Myr because of observational constraints. At this age, the cluster light is dominated by luminous evolved stars, such as red supergiants, with initial masses of \textasciitilde 13-22Msolar for which (primordial) binarity is high. In this study, we investigate to what extent the observed excess velocity dispersion is the result of the orbital motions of binaries. We demonstrate that estimates for the dynamical mass of young star clusters, derived from the observed velocity dispersion, exceed the photometric mass by up to a factor of 10 and are consistent with a constant offset in the square of the velocity dispersion. This can be reproduced by models of virialized star clusters hosting a massive star population of which \textasciitilde 25 per cent is in binaries, with typical mass ratios of \textasciitilde 0.6 and periods of \textasciitilde 1000 d. We conclude that binaries play a pivotal role in deriving the dynamical masses of young (\textasciitilde 10Myr), moderately massive and compact ({$<\sptilde$}105Msolar {$>\sptilde$}1pc) star clusters.}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Solar and Stellar Astrophysics,binaries: general,binaries: spectroscopic,galaxies: star clusters,globular clusters: general,open clusters and associations: general,supergiants}, annotation = {ADS Bibcode: 2010MNRAS.402.1750G}}
@article{gieles_velocity_dispersion_2010, title = {On the Velocity Dispersion of Young Star Clusters: Super-Virial or Binaries?}, shorttitle = {On the Velocity Dispersion of Young Star Clusters}, author = {Gieles, M. and Sana, H. and Portegies Zwart, S. F.}, year = {2010}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {402}, pages = {1750--1757}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2009.15993.x}, urldate = {2023-04-27}, abstract = {Many young extra-galactic clusters have a measured velocity dispersion that is too high for the mass derived from their age and total luminosity, which has led to the suggestion that they are not in virial equilibrium. Most of these clusters are confined to a narrow age range centred around 10Myr because of observational constraints. At this age, the cluster light is dominated by luminous evolved stars, such as red supergiants, with initial masses of \textasciitilde 13-22Msolar for which (primordial) binarity is high. In this study, we investigate to what extent the observed excess velocity dispersion is the result of the orbital motions of binaries. We demonstrate that estimates for the dynamical mass of young star clusters, derived from the observed velocity dispersion, exceed the photometric mass by up to a factor of 10 and are consistent with a constant offset in the square of the velocity dispersion. This can be reproduced by models of virialized star clusters hosting a massive star population of which \textasciitilde 25 per cent is in binaries, with typical mass ratios of \textasciitilde 0.6 and periods of \textasciitilde 1000 d. We conclude that binaries play a pivotal role in deriving the dynamical masses of young (\textasciitilde 10Myr), moderately massive and compact ({$<\sptilde$}105Msolar {$>\sptilde$}1pc) star clusters.}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Solar and Stellar Astrophysics,binaries: general,binaries: spectroscopic,galaxies: star clusters,globular clusters: general,open clusters and associations: general,supergiants}, annotation = {ADS Bibcode: 2010MNRAS.402.1750G}}
@article{goan_bayesian_2020, title = {Bayesian {{Neural Networks}}: {{An Introduction}} and {{Survey}}}, shorttitle = {Bayesian {{Neural Networks}}}, author = {Goan, Ethan and Fookes, Clinton}, year = {2020}, journal = {arXiv e-prints}, volume = {arXiv:2006.12024 [cs, stat]}, doi = {10.1007/978-3-030-42553-1_3}, urldate = {2022-03-31}, abstract = {Neural Networks (NNs) have provided state-of-the-art results for many challenging machine learning tasks such as detection, regression and classification across the domains of computer vision, speech recognition and natural language processing. Despite their success, they are often implemented in a frequentist scheme, meaning they are unable to reason about uncertainty in their predictions. This article introduces Bayesian Neural Networks (BNNs) and the seminal research regarding their implementation. Different approximate inference methods are compared, and used to highlight where future research can improve on current methods.}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{golovin_fifth_2023, title = {The {{Fifth Catalogue}} of {{Nearby Stars}} ({{CNS5}})}, author = {Golovin, Alex and Reffert, Sabine and Just, Andreas and Jordan, Stefan and Vani, Akash and Jahrei{\ss}, Hartmut}, year = {2023}, month = feb, journal = {Astronomy \& Astrophysics}, volume = {670}, pages = {A19}, doi = {10.1051/0004-6361/202244250}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics,catalogs,Galaxy: stellar content,Hertzsprung-Russell and C-M diagrams,mass function,solar neighborhood,stars: distances,stars: luminosity function}}
@article{gonzalez_s2d2_2020, title = {{{S2D2}}: {{Small-scale Significant}} Substructure {{DBSCAN Detection I}}. {{NESTs}} Detection in {{2D}} Star-Forming Regions}, shorttitle = {{{S2D2}}}, author = {Gonz{\'a}lez, Marta and Joncour, Isabelle and Buckner, Anne S. M. and Khorrami, Zeinhab and Moraux, Estelle and Lumsden, Stuart L. and Clark, Paul and Oudmaijer, Ren{\'e} D. and Blanco, Jos{\'e} Manuel and {de la Calle}, Ignacio and {Herrera-Fernandez}, Jos{\'e} Mar{\'i}a and Salgado, Jes{\'u}s J. and {Valero-Mart{\'i}n}, Luis and Torres, Zoe and Hacar, {\'A}lvaro and Ulla, Ana}, year = {2020}, month = nov, journal = {arXiv:2011.10574 [astro-ph]}, eprint = {2011.10574}, primaryclass = {astro-ph}, urldate = {2021-01-05}, abstract = {The spatial and dynamical structure of star-forming regions can help provide insights on stellar formation patterns. The amount of data from current and upcoming surveys calls for robust and objective procedures to detect structure, so the results can be statistically analysed and different regions compared. We provide the community with a tool able to detect the small scale significant structure, above random expectation, in star-forming regions, which could be the imprint of the stellar formation process. The tool makes use of the one point correlation function and of nearest neighbour statistics to determine the parameters for the DBSCAN algorithm. The procedure successfully detects significant small scale substructures in heterogeneous regions, fulfilling the goals it was designed for, and providing very reliable structures. The analysis of regions close to complete spatial randomness (\$Q \textbackslash in [0.7,0.87]\$) shows that, even when some structure is present and recovered, it is hardly distinguishable from spurious detection in homogeneous regions due to projection effects. Interpretation should thus be done with care. For concentrated regions, we detect a main structure surrounded by smaller ones, corresponding to the core plus some Poisson fluctuations around it. We argue that these structures do not correspond to the small compact regions we are looking for. In some realistic cases, a more complete hierarchical, multi-scale analysis would be needed to capture the complexity of the region. We have developed implementations of our procedure, and a catalogue of the NESTs (Nested Elementary STructures) detected by it in four star-forming regions (Taurus, IC 348, Upper Scorpius, and Carina), which are publicly available to the community. Implementations of the 3D, and up to 6D versions of the procedure including proper movements are in progress, and will be provided as future work.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\PGLFDCGV\\2011.html}}
@article{gonzalez-samaniego_effect_2020, title = {The Effect of Photoionising Feedback on the Shaping of Hierarchically-Forming Stellar Clusters}, author = {{Gonz{\'a}lez-Samaniego}, Alejandro and {Vazquez-Semadeni}, Enrique}, year = {2020}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2003.12711}, pages = {staa2921}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa2921}, urldate = {2020-10-07}, abstract = {We use two hydrodynamical simulations (with and without photoionising feedback) of the self-consistent evolution of molecular clouds (MCs) undergoing global hierarchical collapse (GHC), to study the effect of the feedback on the structural and kinematic properties of the gas and the stellar clusters formed in the clouds. During this early stage, the evolution of the two simulations is very similar (implying that the feedback from low mass stars does not affect the cloud-scale evolution significantly) and the star-forming region accretes faster than it can convert gas to stars, causing the instantaneous measured star formation efficiency (SFE) to remain low even in the absence of significant feedback. Afterwards, the ionising feedback first destroys the filamentary supply to star-forming hubs and ultimately removes the gas from it, thus first reducing the star formation (SF) and finally halting it. The ionising feedback also affects the initial kinematics and spatial distribution of the forming stars, because the gas being dispersed continues to form stars, which inherit its motion. In the non-feedback simulation, the groups remain highly compact and do not mix, while in the run with feedback, the gas dispersal causes each group to expand, and the cluster expansion thus consists of the combined expansion of the groups. Most secondary star-forming sites around the main hub are also present in the non-feedback run, implying a primordial rather than triggered nature. We do find one example of a peripheral star-forming site that appears only in the feedback run, thus having a triggered origin. However, this appears to be the exception rather than the rule, although this may be an artifact of our simplified radiative transfer scheme.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M5NDRT9V\\2003.html}}
@article{gorski_healpix:_2005, title = {{{HEALPix}}: {{A Framework}} for {{High-Resolution Discretization}} and {{Fast Analysis}} of {{Data Distributed}} on the {{Sphere}}}, shorttitle = {{{HEALPix}}}, author = {G{\'o}rski, K. M. and Hivon, E. and Banday, A. J. and Wandelt, B. D. and Hansen, F. K. and Reinecke, M. and Bartelmann, M.}, year = {2005}, month = apr, journal = {The Astrophysical Journal}, volume = {622}, number = {2}, pages = {759}, issn = {0004-637X}, doi = {10.1086/427976}, urldate = {2019-12-04}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SQJYLTBJ\\427976.html}}
@article{gossage_combined_nodate, title = {Combined {{Effects}} of {{Rotation}} and {{Age Spreads}} on {{Extended Main Sequence Turn Offs}}}, author = {Gossage, Seth and Conroy, Charlie and Dotter, Aaron and {Cabrera-Ziri}, Ivan and Dolphin, Andrew E. and Bastian, Nate and Dalcanton, Julianne J. and Goudfrooij, Paul and Johnson, L. Clifton and Williams, Benjamin F. and Rosenfield, Philip and Kalirai, Jason and Fouesneau, Morgan}, journal = {arXiv:1907.11251 [astro-ph]}, eprint = {1907.11251}, primaryclass = {astro-ph}, doi = {10.5281/zenodo.3472461}, urldate = {2019-11-20}, abstract = {The extended main sequence turn offs (eMSTOs) of several young to intermediate age clusters are examined in the Magellanic Clouds and the Milky Way. We explore the effects of extended star formation (eSF) and a range of stellar rotation rates on the behavior of the color-magnitude diagram (CMD), paying particular attention to the MSTO. We create synthetic stellar populations based on MESA stellar models to simulate observed Hubble Space Telescope and Gaia star cluster data. We model the effect of rotation as a non-parametric distribution, allowing for maximum flexibility. In our models the slow rotators comprise the blueward, and fast rotators the redward portion of the eMSTO. We simulate data under three scenarios: non-rotating eSF, a range of rotation rates with a single age, and a combination of age and rotation effects. We find that two of the five clusters (the youngest and oldest) favor an age spread, but these also achieve the overall worst fits of all clusters. The other three clusters show comparable statistical evidence between rotation and an age spread. In all five cases, a rotation rate distribution alone is capable of qualitatively matching the observed eMSTO structure. In future work, we aim to compare our predicted Vsin(i) with observations in order to better constrain the physics related to stellar rotation.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Z3ZT9ZRT\\1907.html}}
@article{grasser_rho_2021, title = {The \$\textbackslash rho\$ {{Oph}} Region Revisited with {{Gaia EDR3}}}, author = {Grasser, Natalie and Ratzenb{\"o}ck, Sebastian and Alves, Jo{\~a}o and Gro{\ss}schedl, Josefa and Meingast, Stefan and Zucker, Catherine and Hacar, Alvaro and Lada, Charles and Goodman, Alyssa and Lombardi, Marco and Forbes, John C. and Bomze, Immanuel M. and M{\"o}ller, Torsten}, year = {2021}, month = jun, journal = {arXiv:2101.12200 [astro-ph]}, eprint = {2101.12200}, primaryclass = {astro-ph}, urldate = {2021-06-09}, abstract = {Context. Young and embedded stellar populations are important probes of the star formation process. Paradoxically, we have a better census of nearby embedded young populations than the slightly more evolved optically visible young populations. The high accuracy measurements and all-sky coverage of Gaia data are about to change this situation. Aims. This work aims to construct the most complete sample to date of YSOs in the \$\textbackslash rho\$ Oph region. Methods. We compile a catalog of 1114 Ophiuchus YSOs from the literature and crossmatch it with the Gaia EDR3, Gaia-ESO and APOGEE-2 surveys. We apply a multivariate classification algorithm to this catalog to identify new, co-moving population candidates. Results. We find 191 new high-fidelity YSO candidates in the Gaia EDR3 catalog belonging to the \$\textbackslash rho\$ Oph region. The new sources appear to be mainly Class III M-stars and substellar objects and are less extincted than the known members. We find 28 previously unknown sources with disks. The analysis of the proper motion distribution of the entire sample reveals a well-defined bimodality, implying two distinct populations sharing a similar 3D volume. The first population comprises young stars' clusters around the \$\textbackslash rho\$ Ophiuchi star and the main Ophiuchus clouds (L1688, L1689, L1709). In contrast, the second population is older (\$\textbackslash sim\$ 10 Myr), dispersed, has a distinct proper motion, and is possibly from the Upper Sco group. The two populations are moving away from each other at about 4.1 km/s, and will no longer overlap in about 4 Myr. Finally, we flag 17 sources in the literature as impostors, which are sources that exhibit large deviations from the average distance and proper motion properties of the \$\textbackslash rho\$ Oph population. Our results show the importance of accurate 3D space and motion information for improved stellar population analysis. (Abridged)}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QCP7BLWX\\2101.html}}
@article{green_dustmaps_2018, title = {Dustmaps: {{A Python}} Interface for Maps of Interstellar Dust}, shorttitle = {Dustmaps}, author = {Green, Gregory M.}, year = {2018}, month = jun, journal = {Journal of Open Source Software}, volume = {3}, number = {26}, pages = {695}, issn = {2475-9066}, doi = {10.21105/joss.00695}, urldate = {2022-04-04}, abstract = {Green, (2018). dustmaps: A Python interface for maps of interstellar dust . Journal of Open Source Software, 3(26), 695, https://doi.org/10.21105/joss.00695}, langid = {english}}
@article{greenberg_compact_2020, title = {Compact {{Representation}} of {{Uncertainty}} in {{Hierarchical Clustering}}}, author = {Greenberg, Craig S. and Macaluso, Sebastian and Monath, Nicholas and Lee, Ji-Ah and Flaherty, Patrick and Cranmer, Kyle and McGregor, Andrew and McCallum, Andrew}, year = {2020}, month = sep, journal = {arXiv:2002.11661 [physics, stat]}, eprint = {2002.11661}, primaryclass = {physics, stat}, urldate = {2020-10-07}, abstract = {Hierarchical clustering is a fundamental task often used to discover meaningful structures in data, such as phylogenetic trees, taxonomies of concepts, subtypes of cancer, and cascades of particle decays in particle physics. When multiple hierarchical clusterings of the data are possible, it is useful to represent uncertainty in the clustering through various probabilistic quantities, such as the distribution over tree structures and the marginal probabilities of subtrees. Existing approaches represent uncertainty for a range of models; however, they only provide \textbackslash emph\{approximate\} inference. This paper presents dynamic-programming algorithms and proofs for \textbackslash emph\{exact\} inference in hierarchical clustering at small but useful scales. We are able to compute the partition function, MAP hierarchical clustering, and marginal probabilities of sub-hierarchies and clusters. Our method supports a wide range of hierarchical clustering models and only requires a cluster compatibility function. Rather than scaling with the number of hierarchical clusterings of \$N\$ elements ((2N-3)!!), our approach runs in time and space proportional to the significantly smaller powerset of \$N\$. Despite still being large, there are many important applications at the practically-computable range of \$N {$<$} 20\$. We demonstrate the advantages of exact inference on synthetic data of interest to Dasgupta's cost as well as on two real world applications, in particle physics at the Large Hadron Collider at CERN and in cancer genomics.}, archiveprefix = {arxiv}, keywords = {Computer Science - Data Structures and Algorithms,Computer Science - Machine Learning,{Physics - Data Analysis, Statistics and Probability},Statistics - Machine Learning}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NEXKSV3E\\2002.html}}
@article{greenberg_data_2020, title = {Data {{Structures}} \& {{Algorithms}} for {{Exact Inference}} in {{Hierarchical Clustering}}}, author = {Greenberg, Craig S. and Macaluso, Sebastian and Monath, Nicholas and Lee, Ji-Ah and Flaherty, Patrick and Cranmer, Kyle and McGregor, Andrew and McCallum, Andrew}, year = {2020}, month = oct, journal = {arXiv:2002.11661 [physics, stat]}, eprint = {2002.11661}, primaryclass = {physics, stat}, urldate = {2020-10-23}, abstract = {Hierarchical clustering is a fundamental task often used to discover meaningful structures in data, such as phylogenetic trees, taxonomies of concepts, subtypes of cancer, and cascades of particle decays in particle physics. Typically approximate algorithms are used for inference due to the combinatorial number of possible hierarchical clusterings. In contrast to existing methods, we present novel dynamic-programming algorithms for \textbackslash emph\{exact\} inference in hierarchical clustering based on a novel trellis data structure, and we prove that we can exactly compute the partition function, maximum likelihood hierarchy, and marginal probabilities of sub-hierarchies and clusters. Our algorithms scale in time and space proportional to the powerset of \$N\$ elements which is super-exponentially more efficient than explicitly considering each of the (2N-3)!! possible hierarchies. Also, for larger datasets where our exact algorithms become infeasible, we introduce an approximate algorithm based on a sparse trellis that compares well to other benchmarks. Exact methods are relevant to data analyses in particle physics and for finding correlations among gene expression in cancer genomics, and we give examples in both areas, where our algorithms outperform greedy and beam search baselines. In addition, we consider Dasgupta's cost with synthetic data.}, archiveprefix = {arxiv}, keywords = {Computer Science - Data Structures and Algorithms,Computer Science - Machine Learning,{Physics - Data Analysis, Statistics and Probability},Statistics - Machine Learning}, file = {C\:\\Users\\Emily\\Zotero\\storage\\K9E2INGS\\2002.html}}
@article{grudic_great_2022, title = {Great {{Balls}} of {{FIRE I}}: {{The}} Formation of Star Clusters across Cosmic Time in a {{Milky Way-mass}} Galaxy}, shorttitle = {Great {{Balls}} of {{FIRE I}}}, author = {Grudi{\'c}, Michael Y. and Hafen, Zachary and Rodriguez, Carl L. and Guszejnov, D{\'a}vid and Lamberts, Astrid and Wetzel, Andrew and {Boylan-Kolchin}, Michael and {Faucher-Gigu{\`e}re}, Claude-Andr{\'e}}, year = {2022}, month = mar, journal = {arXiv:2203.05732 [astro-ph]}, eprint = {2203.05732}, primaryclass = {astro-ph}, urldate = {2022-03-14}, abstract = {The properties of young star clusters formed within a galaxy are thought to vary in different interstellar medium (ISM) conditions, but the details of this mapping from galactic to cluster scales are poorly understood due to the large dynamic range involved in galaxy and star cluster formation. We introduce a new method for modeling cluster formation in galaxy simulations: mapping giant molecular clouds (GMCs) formed self-consistently in a FIRE-2 MHD galaxy simulation onto a cluster population according to a GMC-scale cluster formation model calibrated to higher-resolution simulations, obtaining detailed properties of the galaxy's star clusters in mass, metallicity, space, and time. We find \$\textbackslash sim 10\textbackslash\%\$ of all stars formed in the galaxy originate in gravitationally-bound clusters overall, and this fraction increases in regions with elevated \$\textbackslash Sigma\_\{\textbackslash rm gas\}\$ and \$\textbackslash Sigma\_\{\textbackslash rm SFR\}\$, because such regions host denser GMCs with higher star formation efficiency. These quantities vary systematically over the history of the galaxy, driving variations in cluster formation. The mass function of bound clusters varies -- no single Schechter-like or power-law distribution applies at all times. In the most extreme episodes, clusters as massive as \$7\textbackslash times 10\^6 M\_\textbackslash odot\$ form in massive, dense clouds with high star formation efficiency. The initial mass-radius relation of young star clusters is consistent with an environmentally-dependent 3D density that increases with \$\textbackslash Sigma\_\{\textbackslash rm gas\}\$ and \$\textbackslash Sigma\_\{\textbackslash rm SFR\}\$. The model does not reproduce the age and metallicity statistics of old (\${$>$}11\textbackslash rm Gyr\$) globular clusters found in the Milky Way, possibly because it forms stars more slowly at \$z{$>$}3\$.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YUV4H8XE\\2203.html}}
@article{grudic_model_2020, title = {A Model for the Formation of Stellar Associations and Clusters from Giant Molecular Clouds}, author = {Grudi{\'c}, Michael Y. and Kruijssen, J. M. Diederik and {Faucher-Gigu{\`e}re}, Claude-Andr{\'e} and Hopkins, Philip F. and Ma, Xiangcheng and Quataert, Eliot and {Boylan-Kolchin}, Michael}, year = {2020}, month = aug, journal = {arXiv:2008.04453 [astro-ph]}, eprint = {2008.04453}, primaryclass = {astro-ph}, urldate = {2020-08-12}, abstract = {We present a large suite of MHD simulations of turbulent, star-forming giant molecular clouds(GMCs) with stellar feedback, extending previous work by simulating 10 different random realizations for each point in the parameter space of cloud mass and size. It is found that oncethe clouds disperse due to stellar feedback, both self-gravitating star clusters and unbound stars generally remain, which arise from the same underlying continuum of substructured stellar density, ie. the hierarchical cluster formation scenario. The fraction of stars that are born within gravitationally-bound star clusters is related to the overall cloud star formation efficiency set by stellar feedback, but has significant scatter due to stochastic variations in the small-scale details of the star-forming gas flow. We use our numerical results to calibrate a model for mapping the bulk properties (mass, size, and metallicity) of self-gravitating GMCs onto the star cluster populations they form, expressed statistically in terms of cloud-level distributions. Synthesizing cluster catalogues from an observed GMC catalogue in M83, we find that this model predicts initial star cluster masses and sizes that are in good agreement with observations, using only standard IMF and stellar evolution models as inputs for feedback. Within our model, the ratio of the strength of gravity to stellar feedback is the key parameter setting the masses of star clusters, and of the various feedback channels direct stellar radiation(photon momentum and photoionization) is the most important on GMC scales.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{grudic_starforge_2020, title = {{{STARFORGE}}: {{Toward}} a Comprehensive Numerical Model of Star Cluster Formation and Feedback}, shorttitle = {{{STARFORGE}}}, author = {Grudi{\'c}, Michael Y. and Guszejnov, D{\'a}vid and Hopkins, Philip F. and Offner, Stella S. R. and {Faucher-Gigu{\`e}re}, Claude-Andr{\'e}}, year = {2020}, month = oct, journal = {arXiv:2010.11254 [astro-ph]}, eprint = {2010.11254}, primaryclass = {astro-ph}, urldate = {2020-10-23}, abstract = {We present STARFORGE (STAR FORmation in Gaseous Environments): a new numerical framework for 3D radiation MHD simulations of star formation that simultaneously follow the formation, accretion, evolution, and dynamics of individual stars in massive giant molecular clouds (GMCs) while accounting for stellar feedback, including jets, radiative heating and momentum, stellar winds, and supernovae. We use the GIZMO code with the MFM mesh-free Lagrangian MHD method, augmented with new algorithms for gravity, timestepping, sink particle formation and accretion, stellar dynamics, and feedback coupling. We survey a wide range of numerical parameters/prescriptions for sink formation and accretion and find very small variations in star formation history and the IMF (except for intentionally-unphysical variations). Modules for mass-injecting feedback (winds, SNe, and jets) inject new gas elements on-the-fly, eliminating the lack of resolution in diffuse feedback cavities otherwise inherent in Lagrangian methods. The treatment of radiation uses GIZMO's radiative transfer solver to track 5 frequency bands (IR, optical, NUV, FUV, ionizing), coupling direct stellar emission and dust emission with gas heating and radiation pressure terms. We demonstrate accurate solutions for SNe, winds, and radiation in problems with known similarity solutions, and show that our jet module is robust to resolution and numerical details, and agrees well with previous AMR simulations. STARFORGE can scale up to massive (\${$>$}10\^5 M\_\textbackslash odot \$) GMCs on current supercomputers while predicting the stellar (\$\textbackslash gtrsim 0.1 M\_\textbackslash odot\$) range of the IMF, permitting simulations of both high- and low-mass cluster formation in a wide range of conditions.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5YAZQWUQ\\2010.html}}
@article{gutierrez_detection_2022, title = {Detection of {{Gravitational Redshift}} in {{Open Cluster}} Non-Degenerate Stars}, author = {Guti{\'e}rrez, Carlos M. and {Ramos-Chernenko}, Nataliya}, year = {2022}, month = mar, journal = {arXiv:2203.01959 [astro-ph, physics:gr-qc]}, eprint = {2203.01959}, primaryclass = {astro-ph, physics:gr-qc}, urldate = {2022-03-07}, abstract = {A key observational prediction of Einstein's Equivalence Principle is that light undergoes redshift when it escapes from a gravitational field. Although astrophysics provides a wide variety of physical conditions in which this redshift should be significant, till very recently the observational evidence for this gravitational effect was limited to the light emitted by the Sun and white dwarfs. \textbackslash textit\{Gaia\}-DR2 astrometric and kinematic data, in combination with other spectroscopic observations, provides a test bench to validate such predictions in statistical terms. The aim of this paper is to analyze several thousand main-sequence and giant stars in open clusters (OCs) to measure the gravitational redshift effect. Observationally, a spectral shift will depend on the stellar mass-to-radius ratio as expected from the theoretical estimation of relativity. After the analysis, the obtained correlation coefficient between theoretical predictions and observations for 28 (51) OCs is \$a= 0.977 \textbackslash pm 0.218\$ (\$0.899 \textbackslash pm 0.137\$). The result has proven to be statistically robust and with little dependence on the details of the methodology or sample selection criteria. This study represents one of the more extensive validations of a fundamental prediction of gravity theories.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,General Relativity and Quantum Cosmology}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YZ7BSLLK\\2203.html}}
@misc{guzik_variable_2023, title = {Variable {{Blue Straggler Stars}} in {{Open Cluster NGC}} 6819 {{Observed}} in the {{Kepler}} '{{Superstamp}}' {{Field}}}, author = {Guzik, Joyce A. and Baran, Andrzej S. and Sanjayan, Sachu and N{\'e}meth, P{\'e}ter and Hedlund, Anne M. and Jackiewicz, Jason and Dauelsberg, Lori R.}, year = {2023}, month = mar, number = {arXiv:2303.01581}, eprint = {2303.01581}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.01581}, urldate = {2023-03-07}, abstract = {NGC 6819 is an open cluster of age 2.4 Gyr that was in the NASA Kepler spacecraft field of view from 2009 to 2013. The central part of the cluster was observed in a 200 x 200 pixel `superstamp' during these four years in 30-minute cadence photometry, providing a unique long time-series high-precision data set. The cluster contains 'blue straggler' stars, i.e., stars on the main sequence above the cluster turnoff that should have left the main sequence to become red giants. We present light curves and pulsation frequency analyses derived from custom photometric reductions for five confirmed cluster members--four blue stragglers and one star near the main-sequence turnoff. Two of these stars show a rich spectrum of \$\textbackslash delta\$ Scuti pulsation modes, with 236 and 124 significant frequencies identified, respectively, while two stars show mainly low-frequency modes, characteristic of \$\textbackslash gamma\$ Doradus variable stars. The fifth star, a known active x-ray binary, shows only several harmonics of two main frequencies. For the two \$\textbackslash delta\$ Scuti stars, we use a frequency separation--mean-density relation to estimate mean density, and then use this value along with effective temperature to derive stellar mass and radius. For the two stars showing low frequencies, we searched for period-spacing sequences that may be representative of gravity-mode or Rossby-mode sequences, but found no clear sequences. The common age for the cluster members, considered along with the frequencies, will provide valuable constraints for asteroseismic analyses, and may shed light on the origin of the blue stragglers.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}}
@article{haghi_lifetimes_2020, title = {The {{Lifetimes}} of {{Star Clusters Born}} with a {{Top-heavy IMF}}}, author = {Haghi, Hosein and Safaei, Ghasem and Zonoozi, Akram Hasani and Kroupa, Pavel}, year = {2020}, month = nov, journal = {The Astrophysical Journal}, volume = {904}, number = {1}, eprint = {2012.07095}, pages = {43}, issn = {1538-4357}, doi = {10.3847/1538-4357/abbfb0}, urldate = {2021-01-05}, abstract = {Several observational and theoretical indications suggest that the initial mass function (IMF) becomes increasingly top-heavy (i.e., overabundant in high-mass stars with mass \$m {$>$} 1M\_\{\textbackslash odot\}\$) with decreasing metallicity and increasing gas density of the forming object. This affects the evolution of globular clusters (GCs) owing to the different mass-loss rates and the number of black holes formed. Previous numerical modeling of GCs usually assumed an invariant canonical IMF. Using the state-of-the-art \$NBODY6\$ code, we perform a comprehensive series of direct \$N\$-body simulations to study the evolution of star clusters, starting with a top-heavy IMF and undergoing early gas expulsion. Utilizing the embedded cluster mass-radius relation of Marks \& Kroupa (2012) for initializing the models, and by varying the degree of top-heaviness, we calculate the minimum cluster mass needed for the cluster to survive longer than 12 Gyr. We document how the evolution of different characteristics of star clusters such as the total mass, the final size, the density, the mass-to-light ratio, the population of stellar remnants, and the survival of GCs is influenced by the degree of top-heaviness. We find that the lifetimes of clusters with different IMFs moving on the same orbit are proportional to the relaxation time to a power of \$x\$ that is in the range of 0.8 to 1. The observed correlation between concentration and the mass function slope in Galactic GCs can be accounted for excellently in models starting with a top-heavy IMF and undergoing an early phase of rapid gas expulsion.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Physics - Computational Physics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\S8H26F46\\2012.html}}
@article{han_putative_2016, title = {{{THE PUTATIVE OLD}}, {{NEARBY CLUSTER LOD\'EN}} 1 {{DOES NOT EXIST}}}, author = {Han, Eunkyu and Curtis, Jason L. and Wright, Jason T.}, year = {2016}, month = jun, journal = {The Astronomical Journal}, volume = {152}, number = {1}, pages = {7}, issn = {1538-3881}, doi = {10.3847/0004-6256/152/1/7}, urldate = {2019-10-02}, abstract = {Astronomers have access to precious few nearby, middle-aged benchmark star clusters. Within 500 pc, there are only NGC 752 and Ruprecht 147 (R147) at 1.5 and 3 Gyr, respectively. The Database for Galactic Open Clusters (WEBDA) also lists Lod\'en 1 as a 2 Gyr cluster at a distance of 360 pc. If this is true, Lod\'en 1 could become a useful benchmark cluster. This work details our investigation of Lod\'en 1. We assembled archival astrometry (PPMXL) and photometry (2MASS, Tycho-2, APASS), and acquired medium resolution spectra for radial velocity measurements with the Robert Stobie Spectrograph at the Southern African Large Telescope. We observed no sign of a cluster main-sequence turnoff or red giant branch among all stars in the field brighter than . Considering the 29 stars identified by L.O. Lod\'en and listed on SIMBAD as the members of Lod\'en 1, we found no compelling evidence of kinematic clustering in proper motion or radial velocity. Most of these candidates are A stars and red giants, and their observed properties are consistent with distant field stars in the direction of Lod\'en 1 in the Galactic plane. We conclude that the old nearby cluster Lod\'en 1 is neither old, nor nearby, nor a cluster.}, langid = {english}}
@misc{hao_nature_2022, title = {On the Nature of Rotation in the {{Praesepe}} Cluster}, author = {Hao, C. J. and Xu, Y. and Bian, S. B. and Hou, L. G. and Lin, Z. H. and Li, Y. J. and Liu, D. J.}, year = {2022}, month = oct, number = {arXiv:2210.01420}, eprint = {2210.01420}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2210.01420}, urldate = {2022-10-17}, abstract = {Although a large number of Galactic open clusters (OCs) have been identified, the internal kinematic properties (e.g., rotation) of almost all the known OCs are still far from clear. With the high-precision astrometric data of Gaia EDR3, we have developed a methodology to unveil the rotational properties of the Praesepe cluster. Statistics of the three-dimensional residual motions of the member stars reveal the presence of Praesepe's rotation and determine its spatial rotation axis. The mean rotation velocity of the Praesepe cluster within its tidal radius is estimated to be 0.2 \$\textbackslash pm\$ 0.05 km s\$\^\{-1\}\$, and the corresponding rotation axis is tilted in relation to the Galactic plane with an angle of 41 \$\textbackslash pm\$ 12 degree. We also analysed the rms rotational velocity of the member stars around the rotation axis, and found that the rotation of the member stars within the tidal radius of Praesepe probably follows the Newton's classical theorems.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{hao_newly_2022, title = {Newly Detected Open Clusters in the {{Galactic}} Disk Using {{Gaia EDR3}}}, author = {Hao, C. J. and Xu, Y. and Wu, Z. Y. and Lin, Z. H. and Liu, D. J. and Li, Y. J.}, year = {2022}, month = apr, journal = {Astronomy \& Astrophysics}, volume = {660}, eprint = {2204.00196}, pages = {A4}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202243091}, urldate = {2022-04-04}, abstract = {The astrometric satellite Gaia recently released part of its third data set, which provides a good opportunity to hunt for more open clusters in the Milky Way. In this work, we conduct a blind search for open clusters in the Galactic disk using a sample-based clustering search method with high spatial resolution, which is especially suited to finding hidden targets. In addition to confirming 1930 previously known open clusters and 82 known globular clusters, 704 new stellar clusters are proposed as potential open clusters at Galactic latitudes of \$|\$b\$|\$ {$<$} 20 \{deg\}. For each of these new open clusters, we present the coordinates, detailed astrometric parameters, and ages, as well as the radial velocity, if available. Our blind search greatly increases the number of Galactic open clusters as objects of study and shows the incompleteness of the open cluster census across our Galaxy}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{hao_open_2022, title = {Open Clusters Housing Classical {{Cepheids}} in {{Gaia DR3}}}, author = {Hao, C. J. and Xu, Y. and Wu, Z. Y. and Lin, Z. H. and Bian, S. B. and Li, Y. J. and Liu, D. J.}, year = {2022}, month = sep, journal = {Astronomy \& Astrophysics}, eprint = {2210.01521}, primaryclass = {astro-ph}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202244570}, urldate = {2022-10-17}, abstract = {The latest Gaia Data Release 3 provides an opportunity to expand the census of Galactic open clusters harboring classical Cepheid variables, thereby bolstering the cosmic distance scale. A comprehensive analysis yielded a total of 50 classical Cepheids associated with 45 open clusters, of which 39 open cluster-classical Cepheid pairs are considered probable, with the remaining 11 pairs considered improbable but worth following up. Two previously identified clusters by us possibly host classical Cepheids (OC-0125/V1788 Cyg and OC-0675/OGLE-BLG-CEP-114). In addition, we identify 38 new open cluster candidates within the Galactic disk.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{hao_sixteen_2020, title = {Sixteen {{Open Clusters Discovered}} with {{Sample-based Clustering Search}} of {{Gaia DR2}}}, author = {Hao, ChaoJie and Xu, Ye and Wu, ZhenYu and He, ZhiHong and Bian, ShuaiBo}, year = {2020}, month = mar, journal = {Publications of the Astronomical Society of the Pacific}, volume = {132}, pages = {034502}, issn = {0004-6280}, doi = {10.1088/1538-3873/ab694d}, urldate = {2020-04-23}, abstract = {Accurate astrometric parameters and photometric data in three bands for more than 1.3 billion sources (mainly stars) were made available in the recent Gaia Data Release 2, allowing us to find new open clusters in the milky Way. We propose a novel sample-based clustering search method with high spatial resolution to search for open clusters (OCs). We used the proposed method to find 16 new OC candidates. Their astrometric parameters are presented, including age, etc.}, keywords = {methods: data analysis,methods: statistical,open clusters and associations: general}}
@article{harris_array_2020, title = {Array Programming with {{NumPy}}}, author = {Harris, Charles R. and Millman, K. Jarrod and {van der Walt}, St{\'e}fan J. and Gommers, Ralf and Virtanen, Pauli and Cournapeau, David and Wieser, Eric and Taylor, Julian and Berg, Sebastian and Smith, Nathaniel J. and Kern, Robert and Picus, Matti and Hoyer, Stephan and {van Kerkwijk}, Marten H. and Brett, Matthew and Haldane, Allan and {del R{\'i}o}, Jaime Fern{\'a}ndez and Wiebe, Mark and Peterson, Pearu and {G{\'e}rard-Marchant}, Pierre and Sheppard, Kevin and Reddy, Tyler and Weckesser, Warren and Abbasi, Hameer and Gohlke, Christoph and Oliphant, Travis E.}, year = {2020}, month = sep, journal = {Nature}, volume = {585}, number = {7825}, pages = {357--362}, publisher = {{Nature Publishing Group}}, issn = {1476-4687}, doi = {10.1038/s41586-020-2649-2}, urldate = {2022-11-14}, abstract = {Array programming provides a powerful, compact and expressive syntax for accessing, manipulating and operating on data in vectors, matrices and higher-dimensional arrays. NumPy is the primary array programming library for the Python language. It has an essential role in research analysis pipelines in fields as diverse as physics, chemistry, astronomy, geoscience, biology, psychology, materials science, engineering, finance and economics. For example, in astronomy, NumPy was an important part of the software stack used in the discovery of gravitational waves1 and in the first imaging of a black hole2. Here we review how a few fundamental array concepts lead to a simple and powerful programming paradigm for organizing, exploring and analysing scientific data. NumPy is the foundation upon which the scientific Python ecosystem is constructed. It is so pervasive that several projects, targeting audiences with specialized needs, have developed their own NumPy-like interfaces and array objects. Owing to its central position in the ecosystem, NumPy increasingly acts as an interoperability layer between such array computation libraries and, together with its application programming interface (API), provides a flexible framework to support the next decade of scientific and industrial analysis.}, copyright = {2020 The Author(s)}, langid = {english}, keywords = {Computational neuroscience,Computational science,Computer science,Software,Solar physics}}
@article{he_blind_allsky_2022, title = {A {{Blind All-sky Search}} for {{Star Clusters}} in {{Gaia EDR3}}: 886 {{Clusters}} within 1.2 Kpc of the {{Sun}}}, shorttitle = {A {{Blind All-sky Search}} for {{Star Clusters}} in {{Gaia EDR3}}}, author = {He, Zhihong and Wang, Kun and Luo, Yangping and Li, Jing and Liu, Xiaochen and Jiang, Qingquan}, year = {2022}, month = jun, journal = {The Astrophysical Journal Supplement Series}, volume = {262}, number = {1}, pages = {7}, doi = {10.48550/arXiv.2206.12170}, urldate = {2022-06-27}, abstract = {Although previous searches for star clusters have been very successful, many clusters are likely still omitted, especially at high Galactic latitude regions. In this work, based on the astrometry of Gaia EDR3, we searched nearby (parallax {$>$} 0.8 mas) all-sky regions, obtaining 886 star clusters, of which 270 candidates have not been cataloged before. At the same time, we have presented the physical parameters of the clusters by fitting theoretical isochrones to their optical magnitudes. More halo members and expanding structures in many star clusters were also found. Most of the new objects are young clusters that are less than 100 million years old. Our work greatly increased the sample size and physical parameters of star clusters in the solar neighborhood, in particular, 46 clusters are newly found with |b| {$>$} 20 deg, which represents an increase of nearly three fold of cluster numbers at high Galactic latitude regions. The cluster parameters and member stars are available at CDS via https://cdsarc.u-strasbg.fr/ftp/vizier.submit//hezh22b/, and the cluster figure sets are available via https://doi.org/10.12149/101133.}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{he_catalogue_2021, title = {A Catalogue of 74 New Open Clusters Found in {{Gaia Data-Release}} 2}, author = {He, Zhi-Hong and Xu, Ye and Hao, Chao-Jie and Wu, Zhen-Yu and Li, Jing-Jing}, year = {2021}, journal = {Research in Astronomy and Astrophysics}, volume = {21}, number = {4}, eprint = {2010.14870}, pages = {093}, urldate = {2021-04-29}, abstract = {Based on astrometric data from Gaia DR2, we employ an unsupervised machine learning method to blindly search for open star clusters in the Milky Way within the Galactic latitude range of |b| {$<$} 20 degrees. In addition to 2,080 known clusters, 74 new open cluster candidates are found. In this work, we present the positions, apparent radii, parallaxes, proper motions and member stars of these candidates (https://cdsarc.u-strasbg.fr/ftp/vizier.submit//new\_OC/). Meanwhile, to obtain the physical parameters of each candidate cluster, stellar isochrones are fit to the photometric data. The results show that the apparent radii and the observed proper motion dispersions of these new candidates are consistent with those of open clusters previously identified in Gaia DR2.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{he_new_2022, title = {New {{Open Cluster}} Candidates {{Found}} in {{Galactic Disk Using Gaia DR2}}/{{EDR3 Data}}}, author = {He, Zhihong and Li, Chunyan and Zhong, Jing and Liu, Guimei and Bai, Leya and Qin, Songmei and Jiang, Yueyue and Zhang, Xi and Chen, Li}, year = {2022}, month = mar, journal = {The Astrophysical Journal Supplement Series}, volume = {260}, number = {1}, eprint = {2203.05177}, pages = {8}, urldate = {2022-03-14}, abstract = {We report 541 new open cluster candidates in Gaia EDR3 through revisiting the cluster results from an earlier analysis of the Gaia DR2, which revealed nearly a thousand open cluster candidates in the solar neighborhood (mostly d {$<$} 3 kpc) resideing at Galactic latitudes |b| {$<$} 20 degrees. A subsequent comparison with lists of known clusters shows a large increases of the cluster samples within 2 kpc from the Sun. We assign membership probabilities to the stars through the open source pyUPMASK algorithm, and also estimate the physical parameters through isochrone fitting for each candidate. Most of the new candidates show small total proper motion dispersions and clear features in the color-magnitude diagrams. Besides, the metallicity gradient of the new candidates is consistent with those found in the literature. The cluster parameters and member stars are available at CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via https://cdsarc.unistra.fr/viz-bin/cat/J/ApJS. The discovery of these new objects shows that the open cluster samples in Gaia data is still not complete, and more discoveries are expected in the future researches.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\EZ8MVNXM\\2203.html}}
@article{he_unveiling_hidden_2022, title = {Unveiling Hidden Stellar Aggregates in the {{Milky Way}}: 1656 New Star Clusters Found in {{Gaia EDR3}}}, shorttitle = {Unveiling Hidden Stellar Aggregates in the {{Milky Way}}}, author = {He, Zhihong and Liu, Xiaochen and Luo, Yangping and Wang, Kun and Jiang, Qingquan}, year = {2022}, month = sep, journal = {The Astrophysical Journal Supplement Series}, volume = {264}, number = {1}, pages = {8}, doi = {10.48550/arXiv.2209.08504}, urldate = {2022-09-22}, abstract = {We report 1,656 new star clusters found in the Galactic disk (|b|{$<$}20 degrees) beyond 1.2 kpc, using Gaia EDR3 data. Based on an unsupervised machine learning algorithm, DBSCAN, and followed our previous studies, we utilized a unique method to do the data preparation and obtained the clustering coefficients, which proved to be an effective way to search blindly for star clusters. We tabulated the physical parameters and member stars of the new clusters, and presented some interesting examples, including a globular cluster candidate. The cluster parameters and member stars are available at CDS via anonymous ftp to https://cdsarc.cds.unistra.fr/ftp/vizier.submit//he22c. We examined the new discoveries and discussed their statistical properties. The proper motion dispersions and radii of the new clusters were the same as the previously reported ones. The new star clusters beyond 1.2 kpc were older than those in the solar neighborhood, and the new objects found in the third Galactic quadrant presented the lowest line-of-sight extinctions. Combined with our previous results, the total population of new clusters detected through our method was 2,541, corresponding to 55\% of all newly published clusters in the Gaia era. The number of cataloged Gaia star clusters was also increased to nearly six thousand. In the near future, it is necessary to make a unified confirmation and member star determination for all reported clusters.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{healy_stellar_2020, title = {Stellar {{Spins}} in the {{Open Cluster NGC}} 2516}, author = {Healy, Brian F. and McCullough, P. R.}, year = {2020}, month = sep, journal = {arXiv:2009.14202 [astro-ph]}, eprint = {2009.14202}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {Measuring the distribution of stellar spin axis orientations in a coeval group of stars probes the physical processes underlying the stars' formation. In this paper, we use spectro-photometric observations of the open cluster NGC 2516 to determine the degree of spin alignment among its stars. We combine \$\textbackslash textit\{TESS\}\$ light curves, ground-based spectroscopy from the Gaia-ESO and GALAH surveys, broad-band stellar magnitudes from several surveys, and \$\textbackslash textit\{Gaia\}\$ astrometry to measure 33 stellar inclinations and quantify overall cluster rotation. Our measurements suggest that stellar spins in this cluster are isotropically oriented, while allowing for the possibility that they are moderately aligned. An isotropic distribution of NGC 2516 spins would imply a star-forming environment in which turbulence dominated ordered motion, while a moderately aligned distribution would suggest a more substantial contribution from rotation. We also perform a three-dimensional analysis of the cluster's internal kinematics, finding no significant signatures of overall rotation. Stemming from this analysis, we identify evidence of cluster contraction, suggesting possible ongoing mass segregation in NGC 2516.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JKS8KMFS\\2009.html}}
@misc{healy_study_2023, title = {A {{Study}} of {{Stellar Spins}} in 15 {{Open Clusters}}}, author = {Healy, Brian F. and McCullough, P. R. and Schlaufman, Kevin C. and Kovacs, Geza}, year = {2023}, month = jan, number = {arXiv:2301.10249}, eprint = {2301.10249}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2301.10249}, urldate = {2023-02-13}, abstract = {We analyze spectroscopic and photometric data to determine the projected inclinations of stars in 11 open clusters, placing constraints on the spin-axis distributions of six clusters. We combine these results with four additional clusters studied by Healy \& McCullough (2020) and Healy et al. (2021) to perform an ensemble analysis of their spins. We find that eight out of ten constrained clusters (80\%) have spin-axis orientations consistent with isotropy, and we establish a lower limit of four out of ten (40\%) isotropic clusters at 75\% confidence, assuming no correlation of spins between clusters. We also identify two clusters whose spin-axis distributions can be better described by a model consisting of an aligned fraction of stars combined with an isotropic distribution. However, the inclination values of these stars may be influenced by systematic error, and the small number of stars modeled as aligned in these two clusters precludes the interpretation that their stellar subsets are physically aligned. Overall, no cluster displays an unambiguous signature of spin alignment, and 97\% of the stars in our sample are consistent with isotropic orientations in their respective clusters. Our results offer support for the dominance of turbulence over ordered rotation in clumps and do not suggest alignment of rotation axes and magnetic fields in protostars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}}
@article{heiter_metallicity_2014, title = {On the Metallicity of Open Clusters: {{II}}. {{Spectroscopy}}{$\star$}}, shorttitle = {On the Metallicity of Open Clusters}, author = {Heiter, U. and Soubiran, C. and Netopil, M. and Paunzen, E.}, year = {2014}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {561}, pages = {A93}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201322559}, urldate = {2021-05-15}, abstract = {Methods. The literature was searched for [Fe/H] estimates of individual member stars of open clusters based on the analysis of highresolution spectra. For comparison, we also compiled [Fe/H] estimates based on spectra with low and intermediate resolution. At medium and high resolution, we found that differences in the analysis methods have a stronger effect on the metallicity than that of quality differences in the observations. We retained only highly probable cluster members and introduced a restriction on atmospheric parameters. Results. We combined 641 individual metallicity values for 458 stars in 78 open clusters from 86 publications to form our final set of high-quality cluster metallicities. The photometric metallicities discussed in the first paper of this series are systematically lower than the spectroscopic ones by about 0.1 dex, and the differences show a scatter of about 0.2 dex. In a preliminary comparison of our spectroscopic sample with models of Galactic chemical evolution, none of the models predicts the observed radial metallicity gradient. Conclusions. Photometric metallicities show a large intrinsic dispersion, while the more accurate spectroscopic sample presented in this paper comprises fewer than half the number of clusters. Only a sophisticated combination of all available photometric and spectroscopic data will allow us to trace the metallicity distribution in the Galactic disk on a local and global scale.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GVAJN23N\\Heiter et al. - 2014 - On the metallicity of open clusters II. Spectrosc.pdf}}
@article{helmi_streams_2020, title = {Streams, Substructures and the Early History of the {{Milky Way}}}, author = {Helmi, Amina}, year = {2020}, month = feb, journal = {arXiv:2002.04340 [astro-ph]}, eprint = {2002.04340}, primaryclass = {astro-ph}, urldate = {2020-02-12}, abstract = {The advent of Gaia's 2nd data release in combination with large spectroscopic surveys are revolutionizing our understanding of the Galaxy. Thanks to these and the knowledge accumulated thus far, a more mature picture of the evolution of the early Milky Way is emerging: * Two of the traditional Galactic components, i.e. the stellar halo and the thick disk, appear to be intimately linked: stars with halo-like kinematics originate in similar proportions, from a "heated" (thick) disk and from debris from a system named Gaia-Enceladus. Gaia-Enceladus was the last big merger event experienced by the Milky Way and probably completed around 10 Gyr ago. The puffed-up stars now present in the halo as a consequence of the merger have thus exposed the existence of a disk component at z \textasciitilde{} 1.8. * The Helmi streams, Sequoia, and Thamnos are amongst the newly uncovered or better characterized merger events. Knowledge of their progenitor's properties, star formation and chemical histories is still incomplete. * Debris' from different objects often overlap in phase-space. A task for the next years will be to use spectroscopic surveys for chemical labelling and to disentangle events from one another using dimensions other than only phase-space, metallicity or [alpha/Fe]. * These surveys will also provide line-of-sight velocities missing for faint stars and more accurate distance determinations for distant objects. The resulting samples of stars will cover a much wider volume of the Galaxy allowing, for example, linking kinematic substructures in the inner halo to spatial overdensities in the outer halo. * All the results obtained so far are in-line with expectations of current cosmological models. Yet, tailored hydrodynamical simulations as well as "constrained" cosmological simulations are needed to push our knowledge of the assembly of the Milky Way back to the earliest times. [abridged]}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RQ4QV879\\2002.html}}
@article{herschel_catalogue_one_1786, title = {Catalogue of One Thousand New Nebulae and Clusters of Stars. {{By}} William Herschel, {{LL}}.{{D}}. {{F}}. {{R}}. {{S}}.}, author = {Herschel, William}, year = {1786}, month = jan, journal = {Philosophical Transactions of the Royal Society of London Series I}, volume = {76}, pages = {457--499}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1786RSPT...76..457H}}
@article{herschel_general_catalogue_1864, title = {A General Catalogue of Nebulae and Clusters of Stars}, author = {Herschel, John Frederick William}, year = {1864}, month = jan, journal = {Philosophical Transactions of the Royal Society of London Series I}, volume = {154}, pages = {1--137}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1864RSPT..154....1H}}
@article{hertzsprung_ueber_verwendung_1911, title = {Ueber Die Verwendung Photographischer Effektiver Wellenlaengen Zur Bestimmung von Farbenaequivalenten}, author = {Hertzsprung, Ejnar}, year = {1911}, month = jan, journal = {Publikationen des Astrophysikalischen Observatoriums zu Potsdam}, volume = {63}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1911POPot..63.....H}, keywords = {STARS: COLOR,STARS: SPECTRA}}
@article{hippel_inverting_2006, title = {Inverting {{Color-Magnitude Diagrams}} to {{Access Precise Star Cluster Parameters}}: {{A Bayesian Approach}}*}, shorttitle = {Inverting {{Color-Magnitude Diagrams}} to {{Access Precise Star Cluster Parameters}}}, author = {von Hippel, Ted and Jefferys, William H. and Scott, James and Stein, Nathan and Winget, D. E. and DeGennaro, Steven and Dam, Albert and Jeffery, Elizabeth}, year = {2006}, month = jul, journal = {The Astrophysical Journal}, volume = {645}, number = {2}, pages = {1436}, issn = {0004-637X}, doi = {10.1086/504369}, urldate = {2019-09-30}, langid = {english}, keywords = {OC Analysis,read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\AQ9RQSFW\\504369.html}}
@article{hirai_sirius_2020, title = {{{SIRIUS}} Project {{I}}: {{Star}} Formation Models for Star-by-Star Simulations of Star Clusters and Galaxy Formation}, shorttitle = {{{SIRIUS}} Project {{I}}}, author = {Hirai, Yutaka and Fujii, Michiko S. and Saitoh, Takayuki R.}, year = {2020}, month = may, journal = {arXiv:2005.12906 [astro-ph]}, eprint = {2005.12906}, primaryclass = {astro-ph}, urldate = {2020-05-29}, abstract = {Most stars are formed as star clusters in galaxies, which then disperse into galactic disks. Upcoming exascale supercomputational facilities will enable performing simulations of galaxies and their formation by resolving individual stars (star-by-star simulations). This will substantially advance our understanding of star formation in galaxies, star cluster formation, and assembly histories of galaxies. In previous galaxy simulations, a simple stellar population approximation was used. It is, however, difficult to improve the mass resolution with this approximation. Therefore, a model for forming individual stars that can be used in simulations of galaxies must be established. In this first paper of a series of the SIRIUS (SImulations Resolving IndividUal Stars) project, we propose and demonstrate a new stochastic star formation model for star-by-star simulations. In this model, an assumed stellar initial mass function (IMF) is randomly assigned to newly formed stars. We then introduce a maximum search radius to assemble the mass from surrounding gas particles to form star particles. In this study, we perform a series of \$N\$-body/smoothed particle hydrodynamics simulations of star cluster formations from turbulent molecular clouds as test cases. The IMF can be correctly sampled if a maximum search radius that is larger than the value estimated from the threshold density for star formation is adopted. In small clouds, the formation of massive stars is highly stochastic because of the small number of stars. We confirm that the star formation efficiency and threshold density do not strongly affect the results. Herein, we demonstrate that our models can be applied to simulations varying from star clusters to galaxies for a wide range of resolutions.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RJGMMN2E\\2005.html}}
@article{hobbs_gaianir_combining_2016, title = {{{GaiaNIR}}: {{Combining}} Optical and near-Infra-Red ({{NIR}}) Capabilities with Time-Delay-Integration ({{TDI}}) Sensors for a Future Gaia-like Mission}, author = {Hobbs, David and H{\o}g, Erik and Mora, Alcione and Crowley, Cian and McMillan, Paul and Ranalli, Piero and Heiter, Ulrike and Jordi, Carme and Hambly, Nigel and Church, Ross and Anthony, Brown and Tanga, Paolo and Chemin, Laurent and Portell, Jordi and {Jim{\'e}nez-Esteban}, Fran and Klioner, Sergei and Mignard, Francois and Fynbo, Johan and Wyrzykowski, {\L}ukasz and Rybicki, Krzysztof and Anderson, Richard I. and Cellino, Alberto and Fabricius, Claus and Davidson, Michael and Lindegren, Lennart}, year = {2016}, month = sep, journal = {arXiv e-prints}, eprint = {1609.07325}, primaryclass = {astro-ph.IM}, pages = {arXiv:1609.07325}, doi = {10.48550/arXiv.1609.07325}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{hog_tycho-2_2000, title = {The {{Tycho-2}} Catalogue of the 2.5 Million Brightest Stars}, author = {H{\o}g, E. and Fabricius, C. and Makarov, V. V. and Urban, S. and Corbin, T. and Wycoff, G. and Bastian, U. and Schwekendiek, P. and Wicenec, A.}, year = {2000}, month = mar, journal = {Astronomy and Astrophysics}, volume = {355}, pages = {L27-L30}, issn = {0004-6361}, urldate = {2020-06-24}, abstract = {The Tycho-2 Catalogue presented here is an astrometric reference catalogue containing positions and proper motions as well as two-colour photometric data for the 2.5 million brightest stars in the sky. The Tycho-2 positions and magnitudes are based on precisely the same observations as the original Tycho Catalogue (hereafter Tycho-1) collected by the star mapper of the ESA Hipparcos satellite, but Tycho-2 is much bigger and slightly more precise, owing to a more advanced reduction technique. Components of double stars with separations down to 0.8 arcsec are included. Proper motions precise to about 2.5 mas/yr are given as derived from a comparison with the Astrographic Catalogue and 143 other ground-based astrometric catalogues, all reduced to the Hipparcos celestial coordinate system. Tycho-2 supersedes in most applications Tycho-1, as well as the ACT and TRC catalogues based on Tycho-1. Based on observations made with the ESA Hipparcos astrometry satellite. The catalogue is distributed on CD-ROM and through the astronomical data centres, and further information is given on the website http://www.astro.ku.dk/\textasciitilde erik/Tycho-2.}, keywords = {ASTROMETRY,CATALOGS,STARS: FUNDAMENTAL PARAMETERS}}
@article{hogg_data_2010, title = {Data Analysis Recipes: {{Fitting}} a Model to Data}, shorttitle = {Data Analysis Recipes}, author = {Hogg, David W. and Bovy, Jo and Lang, Dustin}, year = {2010}, month = aug, journal = {arXiv:1008.4686 [astro-ph, physics:physics]}, eprint = {1008.4686}, primaryclass = {astro-ph, physics:physics}, urldate = {2019-09-03}, abstract = {We go through the many considerations involved in fitting a model to data, using as an example the fit of a straight line to a set of points in a two-dimensional plane. Standard weighted least-squares fitting is only appropriate when there is a dimension along which the data points have negligible uncertainties, and another along which all the uncertainties can be described by Gaussians of known variance; these conditions are rarely met in practice. We consider cases of general, heterogeneous, and arbitrarily covariant two-dimensional uncertainties, and situations in which there are bad data (large outliers), unknown uncertainties, and unknown but expected intrinsic scatter in the linear relationship being fit. Above all we emphasize the importance of having a "generative model" for the data, even an approximate one. Once there is a generative model, the subsequent fitting is non-arbitrary because the model permits direct computation of the likelihood of the parameters or the posterior probability distribution. Construction of a posterior probability distribution is indispensible if there are "nuisance parameters" to marginalize away.}, archiveprefix = {arxiv}, keywords = {Bayesian Statistics Guide,Gaia Usage Guide,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RUCDVNNN\\Hogg et al_2010_Data analysis recipes.pdf;C\:\\Users\\Emily\\Zotero\\storage\\RFM8U92D\\1008.html}}
@article{hoppe_solar_2020, title = {The Solar Abundance Problem and {{eMSTOs}} in Clusters}, author = {Hoppe, R. and Bergemann, M. and Bitsch, B. and Serenelli, A.}, year = {2020}, month = jul, journal = {arXiv:2007.01297 [astro-ph]}, eprint = {2007.01297}, primaryclass = {astro-ph}, urldate = {2020-07-06}, abstract = {We study the impact of accretion from protoplanetary discs on stellar evolution of AFG-type stars. We use a simplified disc model computed using the Two-Pop-Py code that contains the growth and drift of dust particles in the protoplanetary disc. It is used to model the accretion scenarios for a range of physical conditions of protoplanetary discs. Two limiting cases are combined with the evolution of stellar convective envelopes computed using the Garstec stellar evolution code. We find that the accretion of metal-poor (gas) or metal-rich (dust) material has a significant impact on the chemical composition of the stellar convective envelope. As a consequence, the evolutionary track of the star diverts from the standard scenario predicted by canonical stellar evolution models, which assume a constant and homogeneous chemical composition after the assembly of the star has finished. In the case of the Sun, we find a modest impact on the solar chemical composition. Accretion of metal-poor material indeed reduces the overall metallicity of the solar atmosphere, and it is consistent, within the uncertainty, with the solar Z reported by Caffau et al. (2011), but our model is not consistent with the measurement by Asplund et al. (2009). Another effect is the change of the position of the star in the colour-magnitude diagram. We compare our predictions to a set of open clusters from the Gaia DR2 and show that it is possible to produce a scatter close to the turn-off of young clusters that could contribute to explain the observed scatter in CMDs. Detailed measurements of metallicities and abundances in the nearby open clusters will provide a stringent observational test of our proposed scenario.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NL4BTK3F\\2007.html}}
@article{horta_linking_2020, title = {Linking Globular Cluster Formation at Low and High Redshift through the Age-Metallicity Relation in {{E-MOSAICS}}}, author = {Horta, Danny and Hughes, Meghan E. and Pfeffer, Joel L. and Bastian, Nate and Kruijssen, J. M. Diederik and {Reina-Campos}, Marta and Crain, Rob A.}, year = {2020}, month = oct, journal = {arXiv:2010.10522 [astro-ph]}, eprint = {2010.10522}, primaryclass = {astro-ph}, urldate = {2020-10-22}, abstract = {We set out to compare the age-metallicity relation (AMR) of massive clusters from Magellanic Cloud mass galaxies in the E-MOSAICS suite of numerical cosmological simulations with an amalgamation of observational data of massive clusters in the Large and Small Magellanic Clouds (LMC/SMC). We aim to test if: i) star cluster formation proceeds according to universal physical processes, suggestive of a common formation mechanism for young-massive clusters (YMCs), intermediate-age clusters (IACs), and ancient globular clusters (GCs); ii) massive clusters of all ages trace a continuous AMR; iii) the AMRs of smaller mass galaxies show a shallower relation when compared to more massive galaxies. Our results show that, within the uncertainties, the predicted AMRs of L/SMC-mass galaxies with similar star formation histories to the L/SMC follow the same relation as observations. We also find that the metallicity at which the AMR saturates increases with galaxy mass, which is also found for the field star AMRs. This suggests that relatively low-metallicity clusters can still form in dwarfs galaxies. Given our results, we suggest that ancient GCs share their formation mechanism with IACs and YMCs, in which GCs are the result of a universal process of star cluster formation during the early episodes of star formation in their host galaxies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\W8S2E8H8\\2010.html}}
@article{hosek_jr_pypopstar_2020, title = {{{PyPopStar}}: {{A Python-Based Simple Stellar Population Synthesis Code}} for {{Star Clusters}}}, shorttitle = {{{PyPopStar}}}, author = {Hosek Jr, M. W. and Lu, J. R. and Lam, C. Y. and Gautam, A. K. and Lockhart, K. E. and Kim, D. and Jia, S.}, year = {2020}, month = jun, journal = {The Astronomical Journal}, volume = {160}, number = {3}, eprint = {2006.06691}, pages = {143}, urldate = {2020-06-15}, abstract = {We present PyPopStar, an open-source Python package that simulates simple stellar populations. The strength of PyPopStar is its modular interface which offers the user control of 13 input properties including (but not limited to) the Initial Mass Function, stellar multiplicity, extinction law, and the metallicity-dependent stellar evolution and atmosphere model grids used. The user also has control over the Initial-Final Mass Relation in order to produce compact stellar remnants (black holes, neutron stars, and white dwarfs). We demonstrate several outputs produced by the code, including color-magnitude diagrams, HR-diagrams, luminosity functions, and mass functions. PyPopStar is object-oriented and extensible, and we welcome contributions from the community. The code and documentation are available on GitHub and ReadtheDocs, respectively.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Y42SDVJN\\2006.html}}
@article{hottier_fedred_2020, title = {{{FEDReD II}} : {{3D Extinction Map}} with {{2MASS}} and {{Gaia DR2}} Data}, shorttitle = {{{FEDReD II}}}, author = {Hottier, C. and Babusiaux, C. and Arenou, F.}, year = {2020}, month = jul, journal = {arXiv:2007.03734 [astro-ph]}, eprint = {2007.03734}, primaryclass = {astro-ph}, urldate = {2020-07-09}, abstract = {Aims. We aim to map the 3D distribution of the interstellar extinction of the Milky Way disk up to distances larger than those probed with the Gaia parallax alone. Methods. We apply the FEDReD (Field Extinction-Distance Relation Deconvolver) algorithm to the 2MASS near-infrared photometry together with the Gaia DR2 astrometry and photometry. This algorithm uses a Bayesian deconvolution approach, based on an empirical HR-diagram representative of the local thin disk, in order to map the extinction as a function of distance of various fields of view. Results. We analysed more than 5.6 million stars to obtain an extinction map of the entire Galactic disk within \$|b|{$<$}0.24\^\{\textbackslash circ\}\$. This map provides information up to \$5\textasciitilde\textbackslash mathrm\{kpc\}\$ in the direction of the Galactic centre and at more than \$7\textasciitilde\textbackslash mathrm\{kpc\}\$ in the direction of the anticentre. This map reveals the complete shape of structures known locally, such as the Vela complex or the split of the local arm. Furthermore our extinction map shows many large "clean bubbles" especially one in the Sagittarius -- Carina complex, and four others which define a structure that we nickname the butterfly.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\ARGYR9F7\\2007.html}}
@article{hron_variational_2017, title = {Variational {{Gaussian Dropout}} Is Not {{Bayesian}}}, author = {Hron, Jiri and Matthews, Alexander G. de G. and Ghahramani, Zoubin}, year = {2017}, month = nov, journal = {arXiv e-prints}, volume = {arXiv:1711.02989}, urldate = {2022-03-31}, abstract = {Gaussian multiplicative noise is commonly used as a stochastic regularisation technique in training of deterministic neural networks. A recent paper reinterpreted the technique as a specific algorithm for approximate inference in Bayesian neural networks; several extensions ensued. We show that the log-uniform prior used in all the above publications does not generally induce a proper posterior, and thus Bayesian inference in such models is ill-posed. Independent of the log-uniform prior, the correlated weight noise approximation has further issues leading to either infinite objective or high risk of overfitting. The above implies that the reported sparsity of obtained solutions cannot be explained by Bayesian or the related minimum description length arguments. We thus study the objective from a non-Bayesian perspective, provide its previously unknown analytical form which allows exact gradient evaluation, and show that the later proposed additive reparametrisation introduces minima not present in the original multiplicative parametrisation. Implications and future research directions are discussed.}, keywords = {Statistics - Machine Learning}}
@article{hu_deciphering_2021, title = {Deciphering {{Star Cluster Evolution}} by {{Shape Morphology}}}, author = {Hu, Qingshun and Zhang, Yu and Esamdin, Ali and Liu, Jinzhong and Zeng, Xiangyun}, year = {2021}, month = mar, journal = {arXiv:2103.02912 [astro-ph]}, eprint = {2103.02912}, primaryclass = {astro-ph}, urldate = {2021-03-08}, abstract = {We analyze the morphological evolution of open clusters and provide shape parameters for 265 open clusters. The results show that the overall shape of sample clusters becomes more elliptical as they grow older, while their core remains circular or slightly trend to circularize. There is a negative correlation of the ellipticities with the number of members of the sample clusters. A significant negative correlation between the overall ellipticities and masses is also detected for the sample clusters with log(age/year) \$\textbackslash geq\$ 8, suggesting that the overall shapes of the clusters are possibly influenced by the number of members and masses, in addition to the external forces and the surrounding environment. For most young sample clusters, the radial stratification degree of the short axis direction is greater than that of the long, implying that the radial stratification degree in the two directions within the young sample cluster may be unevenly affected by an internal evolutionary process. Older sample clusters exhibit lower stratification in the tangential direction, which possibly means those clusters may continue to survive for a long time at a low level of stratification. Our analysis shows that the overall shape of the sample clusters may be more susceptible to the influence of Galactic tides toward the Galactic center than the shear forces embedded in Galactic differential rotation. By analyzing the distribution of the ages and number of members of star clusters, we suggest that NGC 6791 may originate from superclusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TM5UV72P\\2103.html}}
@article{huang_search_2020, title = {Search for Globular Clusters Associated with the {{Milky Way}} Dwarf Galaxies Using {{Gaia DR2}}}, author = {Huang, Kuan-Wei and Koposov, Sergey E.}, year = {2020}, month = oct, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2005.14014}, pages = {staa3297}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa3297}, urldate = {2020-11-30}, abstract = {We report the result of searching for globular clusters (GCs) around 55 Milky Way satellite dwarf galaxies within the distance of 450 kpc from the Galactic Center except for the Large and Small Magellanic Clouds and the Sagittarius dwarf. For each dwarf, we analyze the stellar distribution of sources in Gaia DR2, selected by magnitude, proper motion, and source morphology. Using the kernel density estimation of stellar number counts, we identify eleven possible GC candidates. Crossed-matched with existing imaging data, all eleven objects are known either GCs or galaxies and only Fornax GC 1-6 among them are associated with the targeted dwarf galaxy. Using simulated GCs, we calculate the GC detection limit \$M\_\{\textbackslash rm V\}\^\{\textbackslash rm lim\}\$ that spans the range from \$M\_\{\textbackslash rm V\}\^\{\textbackslash rm lim\} \textbackslash sim -7\$ for distant dwarfs to \$M\_\{\textbackslash rm V\}\^\{\textbackslash rm lim\} \textbackslash sim 0\$ for nearby systems. Assuming a Gaussian GC luminosity function, we compute that the completeness of the GC search is above 90 percent for most dwarf galaxies. We construct the 90 percent credible intervals/upper limits on the GC specific frequency \$S\_\{\textbackslash rm N\}\$ of the MW dwarf galaxies: \$12 {$<$} S\_\{\textbackslash rm N\} {$<$} 47\$ for Fornax, \$S\_\{\textbackslash rm N\} {$<$} 20\$ for the dwarfs with \$-12 {$<$} M\_\{\textbackslash rm V\} {$<$} -10\$, \$S\_\{\textbackslash rm N\} {$<$} 30\$ for the dwarfs with \$-10 {$<$} M\_\{\textbackslash rm V\} {$<$} -7\$, and \$S\_\{\textbackslash rm N\} {$<$} 90\$ for the dwarfs with \$M\_\{\textbackslash rm V\} {$>$} -7\$. Based on \$S\_\{\textbackslash rm N\}\$, we derive the probability of galaxies hosting GCs given their luminosity, finding that the probability of galaxies fainter than \$M\_\{\textbackslash rm V\} = -9\$ to host GCs is lower than 0.1.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\79G35LFU\\2005.html}}
@article{huertas-company_hubble_2019, title = {The {{Hubble Sequence}} at z {$\sim$} 0 in the {{IllustrisTNG}} Simulation with Deep Learning}, author = {{Huertas-Company}, Marc and {Rodriguez-Gomez}, Vicente and Nelson, Dylan and Pillepich, Annalisa and Bottrell, Connor and Bernardi, Mariangela and {Dom{\'i}nguez-S{\'a}nchez}, Helena and Genel, Shy and Pakmor, Ruediger and Snyder, Gregory F. and Vogelsberger, Mark}, year = {2019}, month = oct, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {489}, pages = {1859--1879}, issn = {0035-8711}, doi = {10.1093/mnras/stz2191}, urldate = {2022-12-19}, abstract = {We analyse the optical morphologies of galaxies in the IllustrisTNG simulation at z {$\sim$} 0 with a convolutional neural network trained on visual morphologies in the Sloan Digital Sky Survey. We generate mock SDSS images of a mass complete sample of {$\sim$} 12 000 galaxies in the simulation using the radiative transfer code SKIRT and include PSF and noise to match the SDSS r-band properties. The images are then processed through the exact same neural network used to estimate SDSS morphologies to classify simulated galaxies in four morphological classes (E, S0/a, Sab, Scd). The CNN model classifies simulated galaxies in one of the four main classes with the same uncertainty as for observed galaxies. The mass-size relations of the simulated galaxies divided by morphological type also reproduce well the slope and the normalization of observed relations which confirms a reasonable diversity of optical morphologies in the TNG suite. However we find a weak correlation between optical morphology and Sersic index in the TNG suite as opposed to SDSS which might require further investigation. The stellar mass functions (SMFs) decomposed into different morphologies still show some discrepancies with observations especially at the high-mass end. We find an overabundance of late-type galaxies ({$\sim$} 50\{\{ per cent\}\} versus {$\sim$} 20\{\{ per cent\}\}) at the high-mass end [log(M*/M{$\odot$}) {$>$} 11] of the SMF as compared to observations according to the CNN classifications and a lack of S0 galaxies ({$\sim$} 20\{\{ per cent\}\} versus {$\sim$} 40\{\{ per cent\}\}) at intermediate masses. This work highlights the importance of detailed comparisons between observations and simulations in comparable conditions.}, keywords = {Astrophysics - Astrophysics of Galaxies,galaxies: abundances,galaxies: formation,galaxies: photometry}, annotation = {ADS Bibcode: 2019MNRAS.489.1859H}}
@article{hunt_improving_2021, title = {Improving the Open Cluster Census: {{I}}. {{Comparison}} of Clustering Algorithms Applied to {{{\emph{Gaia}}}} {{DR2}} Data}, shorttitle = {Improving the Open Cluster Census}, author = {Hunt, Emily L. and Reffert, Sabine}, year = {2021}, month = feb, journal = {Astronomy \& Astrophysics}, volume = {646}, pages = {A104}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202039341}, urldate = {2021-02-17}, abstract = {Methods. We selected DBSCAN, HDBSCAN, and Gaussian mixture models for further study, owing to their speed and appropriateness for use with Gaia data. We developed a preprocessing pipeline for Gaia data and developed the algorithms further for the specific application to open clusters. We derived detection rates for all 1385 open clusters in the fields in our study as well as more detailed performance statistics for 100 of these open clusters. Results. DBSCAN was sensitive to 50\%\textendash 62\% of the true positive open clusters in our sample, with generally very good specificity and precision. HDBSCAN traded precision for a higher sensitivity of up to 82\%, especially across different distances and scales of open clusters. Gaussian mixture models were slow and only sensitive to 33\% of open clusters in our sample, which tended to be larger objects. Additionally, we report on 41 new open cluster candidates detected by HDBSCAN, three of which are closer than 500 pc. Conclusions. When used with additional post-processing to mitigate its false positives, we have found that HDBSCAN is the most sensitive and effective algorithm for recovering open clusters in Gaia data. Our results suggest that many more new and already reported open clusters have yet to be detected in Gaia data.}, copyright = {All rights reserved}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NFVDY6KH\\Hunt and Reffert - 2021 - Improving the open cluster census I. Comparison o.pdf}}
@article{hunt_improving_open_2023, title = {Improving the Open Cluster Census. {{II}}. {{An}} All-Sky Cluster Catalogue with {{Gaia DR3}}}, author = {Hunt, Emily L. and Reffert, Sabine}, year = {2023}, month = mar, journal = {arXiv e-prints}, eprint = {2303.13424}, primaryclass = {astro-ph.GA}, pages = {arXiv:2303.13424}, doi = {10.48550/arXiv.2303.13424}, archiveprefix = {arxiv}, copyright = {All rights reserved}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{hunt_power_2020, title = {The Power of Co-Ordinate Transformations in Dynamical Interpretations of {{Galactic}} Structure}, author = {Hunt, Jason A. S. and Johnston, Kathryn V. and Pettitt, Alex R. and Cunningham, Emily C. and Kawata, Daisuke and Hogg, David W.}, year = {2020}, month = jun, journal = {arXiv:2006.03600 [astro-ph]}, eprint = {2006.03600}, primaryclass = {astro-ph}, urldate = {2020-06-09}, abstract = {\$Gaia\$ DR2 has provided an unprecedented wealth of information about the positions and motions of stars in our Galaxy, and has highlighted the degree of disequilibria in the disc. As we collect data over a wider area of the disc it becomes increasingly appealing to start analysing stellar actions and angles, which specifically label orbit space, instead of their current phase space location. Conceptually, while \$\textbackslash bar\{x\}\$ and \$\textbackslash bar\{v\}\$ tell us about the potential and local interactions, grouping in action puts together stars that have similar frequencies and hence similar responses to dynamical effects occurring over several orbits. Grouping in actions and angles refines this further to isolate stars which are travelling together through space and hence have shared histories. Mixing these coordinate systems can confuse the interpretation. For example, it has been suggested that by moving stars to their guiding radius, the Milky Way spiral structure is visible as ridge-like overdensities in the \$Gaia\$ data \textbackslash citep\{Khoperskov+19b\}. However, in this work, we show that these features are in fact the known kinematic moving groups, both in the \$L\_z-\textbackslash phi\$ and the \$v\_\{\textbackslash mathrm\{R\}\}-v\_\{\textbackslash phi\}\$ planes. Using simulations we show how this distinction will become even more important as we move to a global view of the Milky Way. As an example, we show that the radial velocity wave seen in the Galactic disc in \$Gaia\$ and APOGEE should become stronger in the action-angle frame, and that it can be reproduced by transient spiral structure.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\X5JVRTMP\\2006.html}}
@article{hunter_matplotlib_2007, title = {Matplotlib: {{A 2D}} Graphics Environment}, author = {Hunter, J. D.}, year = {2007}, journal = {Computing in Science \& Engineering}, volume = {9}, number = {3}, pages = {90--95}, publisher = {{IEEE COMPUTER SOC}}, doi = {10.1109/MCSE.2007.55}, abstract = {Matplotlib is a 2D graphics package used for Python for application development, interactive scripting, and publication-quality image generation across user interfaces and operating systems.}}
@article{hutchison_hdbscan_2013, title = {{{HDBSCAN}} - {{Density-Based Clustering Based}} on {{Hierarchical Density Estimates}}}, author = {Campello, Ricardo J. G. B. and Moulavi, Davoud and Sander, Joerg}, editor = {Pei, Jian and Tseng, Vincent S. and Cao, Longbing and Motoda, Hiroshi and Xu, Guandong}, year = {2013}, journal = {Advances in Knowledge Discovery and Data Mining}, volume = {7819}, pages = {160--172}, doi = {10.1007/978-3-642-37456-2_14}, urldate = {2019-09-04}, abstract = {We propose a theoretically and practically improved densitybased, hierarchical clustering method, providing a clustering hierarchy from which a simplified tree of significant clusters can be constructed. For obtaining a ``flat'' partition consisting of only the most significant clusters (possibly corresponding to different density thresholds), we propose a novel cluster stability measure, formalize the problem of maximizing the overall stability of selected clusters, and formulate an algorithm that computes an optimal solution to this problem. We demonstrate that our approach outperforms the current, state-of-the-art, density-based clustering methods on a wide variety of real world data.}, collaborator = {Hutchison, David and Kanade, Takeo and Kittler, Josef and Kleinberg, Jon M. and Mattern, Friedemann and Mitchell, John C. and Naor, Moni and Nierstrasz, Oscar and Pandu Rangan, C. and Steffen, Bernhard and Sudan, Madhu and Terzopoulos, Demetri and Tygar, Doug and Vardi, Moshe Y. and Weikum, Gerhard}, langid = {english}, keywords = {Clustering Algorithm,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2C3CHH5Y\\Campello et al. - 2013 - HDBSCAN - Density-Based Clustering Based on Hierar.pdf;C\:\\Users\\Emily\\Zotero\\storage\\65S4CCAB\\Campello et al. - 2013 - HDBSCAN - Density-Based Clustering Based on Hierar_annotated.pdf}}
@incollection{hutter_model-based_2021, title = {Model-{{Based Clustering}} with {{HDBSCAN}}*}, booktitle = {Machine {{Learning}} and {{Knowledge Discovery}} in {{Databases}}}, author = {Strobl, Michael and Sander, J{\"o}rg and Campello, Ricardo J. G. B. and Za{\"i}ane, Osmar}, editor = {Hutter, Frank and Kersting, Kristian and Lijffijt, Jefrey and Valera, Isabel}, year = {2021}, volume = {12458}, pages = {364--379}, publisher = {{Springer International Publishing}}, address = {{Cham}}, doi = {10.1007/978-3-030-67661-2_22}, urldate = {2022-04-02}, isbn = {978-3-030-67660-5 978-3-030-67661-2}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\8SZMXJ5J\\Strobl et al. - 2021 - Model-Based Clustering with HDBSCAN.pdf}}
@article{ilin_flares_2020, title = {Flares in {{Open Clusters}} with {{K2}}. {{II}}. {{Pleiades}}, {{Hyades}}, {{Praesepe}}, {{Ruprecht}} 147, and {{M67}}}, author = {Ilin, Ekaterina and Schmidt, Sarah J. and Poppenh{\"a}ger, Katja and Davenport, James R. A. and Kristiansen, Martti H. and Omohundro, Mark}, year = {2020}, month = oct, journal = {arXiv:2010.05576 [astro-ph]}, eprint = {2010.05576}, primaryclass = {astro-ph}, urldate = {2020-10-13}, abstract = {Flares, energetic eruptions on the surfaces of stars, are an unmistakable manifestation of magnetically driven emission. Their occurrence rates and energy distributions trace stellar characteristics such as mass and age. But before flares can be used to constrain stellar properties, the flaring-age-mass relation requires proper calibration. This work sets out to quantify flaring activity of independently age-dated main sequence stars for a broad range of spectral types using optical light curves obtained by the Kepler satellite. Drawing from the complete K2 archive, we searched 3435 \$\textbackslash sim 80\$ day long light curves of 2111 open cluster members for flares using the open-source software packages K2SC to remove instrumental and astrophysical variability from K2 light curves, and AltaiPony to search and characterize the flare candidates. We confirmed a total of 3844 flares on high probability open cluster members with ages from zero age main sequence (Pleiades) to 3.6 Gyr (M67). We extended the mass range probed in the first study of this series to span from Sun-like stars to mid-M dwarfs. We added the Hyades (690 Myr) to the sample as a comparison cluster to Praesepe (750 Myr), the 2.6 Gyr old Ruprecht 147, and several hundred light curves from the late K2 Campaigns in the remaining clusters. The flare energy distribution was similar in the entire parameter space, following a power law relation with exponent \$\textbackslash alpha\textbackslash approx 1.84-2.39\$. The flaring rates declined with age, and declined faster for higher mass stars. We found evidence that a rapid decline in flaring activity occurred in M1-M2 dwarfs around Hyades/Praesepe age, when these stars spun down to rotation periods of about 10 days, while higher mass stars had already transitioned to lower flaring rates, and lower mass stars still resided in the saturated activity regime. (abridged)}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QAQAMTUE\\2010.html}}
@book{ivezic_statistics_data_2020, title = {Statistics, {{Data Mining}}, and {{Machine Learning}} in {{Astronomy}}. {{A Practical Python Guide}} for the {{Analysis}} of {{Survey Data}}, {{Updated Edition}}}, author = {Ivezi{\'c}, {\v Z}eljko and Connolly, Andrew J. and VanderPlas, Jacob T. and Gray, Alexander}, year = {2020}, month = jan, journal = {Statistics}, urldate = {2023-04-06}, abstract = {Statistics, Data Mining, and Machine Learning in Astronomy is the essential introduction to the statistical methods needed to analyze complex data sets from astronomical surveys such as the Panoramic Survey Telescope and Rapid Response System, the Dark Energy Survey, and the Large Synoptic Survey Telescope. Now fully updated, it presents a wealth of practical analysis problems, evaluates the techniques for solving them, and explains how to use various approaches for different types and sizes of data sets. Python code and sample data sets are provided for all applications described in the book. The supporting data sets have been carefully selected from contemporary astronomical surveys and are easy to download and use. The accompanying Python code is publicly available, well documented, and follows uniform coding standards. Together, the data sets and code enable readers to reproduce all the figures and examples, engage with the different methods, and adapt them to their own fields of interest.An accessible textbook for students and an indispensable reference for researchers, this updated edition features new sections on deep learning methods, hierarchical Bayes modeling, and approximate Bayesian computation. The chapters have been revised throughout and the astroML code has been brought completely up to date.}, keywords = {Astronomy,space and time}, annotation = {ADS Bibcode: 2020sdmm.book.....I}}
@article{jackson_gaia-eso_2020, title = {The {{Gaia-ESO Survey}}: {{Membership}} Probabilities for Stars in 32 Open Clusters from {{3D}} Kinematics}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Jackson, R. J. and Jeffries, R. D. and Wright, N. J. and Randich, S. and Sacco, G. and Pancino, E. and {Cantat-Gaudin}, T. and Gilmore, G. and Vallenari, A. and Bensby, T. and Bayo, A. and Costado, M. T. and Franciosini, E. and Gonneau, A. and Hourihane, A. and Lewis, J. and Monaco, L. and Morbidelli, L. and Worley, C.}, year = {2020}, month = jun, journal = {arXiv:2006.09423 [astro-ph]}, eprint = {2006.09423}, primaryclass = {astro-ph}, urldate = {2020-06-18}, abstract = {The Gaia-ESO Survey (GES) observed many open clusters as part of its programme to spectroscopically characterise the various Milky Way populations. GES spectroscopy and Gaia astrometry from its second data release are used here to assign membership probabilities to targets towards 32 open clusters with ages from 1-3800 Myr, based on maximum likelihood modelling of the 3D kinematics of the cluster and field populations. From a parent catalogue of 14398 individual targets, 5033 stars with uniformly determined 3D velocities, \$T\_\{\textbackslash rm eff\}\$, \$\textbackslash log g\$ and chemistry are assigned cluster membership with probability \${$>$}0.9\$, and with an average probability of 0.991. The robustness of the membership probabilities is demonstrated using independent membership criteria (lithium and parallax) in two of the youngest clusters. The addition of radial velocities improves membership discrimination over proper motion selection alone, especially in more distant clusters. The kinematically-selected nature of the membership lists, independent of photometry and chemistry, makes the catalogue a valuable resource for testing stellar evolutionary models and investigating the time evolution of various parameters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\8LU5NCLV\\2006.html}}
@article{jackson_gaia-eso_2021, title = {The {{Gaia-ESO Survey}}: {{Membership}} Probabilities for Stars in 63 Open and 7 Globular Clusters from {{3D}} Kinematics}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Jackson, R. J. and Jeffries, R. D. and Wright, N. J. and Randich, S. and Sacco, G. and Bragaglia, A. and Hourihane, A. and Tognelli, E. and Degl'Innocenti, S. and Moroni, P. G. Prada and Gilmore, G. and Bensby, T. and Pancino, E. and Smiljanic, R. and Bergemann, M. and Carraro, G. and Franciosini, E. and Gonneau, A. and Jofr{\'e}, P. and Lewis, J. and Magrini, L. and Morbidelli, L. and Prisinzano, L. and Worley, C. and Zaggia, S. and Tautvai{\v s}iene, G. and Albarr{\'a}n, M. L. Guti{\'e}rrez and Montes, D. and {Jim{\'e}nez-Esteban}, F.}, year = {2021}, month = oct, journal = {arXiv:2110.10477 [astro-ph]}, eprint = {2110.10477}, primaryclass = {astro-ph}, urldate = {2021-10-28}, abstract = {Spectroscopy from the final internal data release of the Gaia-ESO Survey (GES) has been combined with Gaia EDR3 to assign membership probabilities to targets observed towards 63 Galactic open clusters and 7 globular clusters. The membership probabilities are based chiefly on maximum likelihood modelling of the 3D kinematics of the targets, separating them into cluster and field populations. From 43211 observed targets, 13985 are identified as highly probable cluster members (\$P{$>$}0.9\$), with an average membership probability of 0.993. The addition of GES radial velocities successfully drives down the fraction of false positives and we achieve better levels of discrimination in most clusters over the use of astrometric data alone, especially those at larger distances. Since the membership selection is almost purely kinematic, the union of this catalogue with GES and Gaia is ideal for investigating the photometric and chemical properties of clusters as a function of stellar mass, age and Galactic position.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GUMH9XM4\\2110.html}}
@article{jaehnig_membership_2021, title = {Membership Lists for 431 Open Clusters in {{Gaia DR2}} Using Extreme Deconvolution Gaussian Mixture Models}, author = {Jaehnig, Karl and Bird, Jonathan and {Holley-Bockelmann}, Kelly}, year = {2021}, month = aug, journal = {The Astrophysical Journal}, volume = {923}, number = {1}, eprint = {2108.02783}, pages = {129}, urldate = {2021-09-15}, abstract = {Open clusters are groups of stars that form at the same time, making them an ideal laboratory to test theories of star formation, stellar evolution, and dynamics in the Milky Way disk. However, the utility of an open cluster can be limited by the accuracy and completeness of its known members. Here, we employ a "top-down" technique, \{\textbackslash it extreme deconvolution gaussian mixture models\} (XDGMM), to extract and evaluate known open clusters from Gaia DR2 by fitting the distribution of stellar parallax and proper motion along a line-of-sight. Extreme deconvolution techniques can recover the intrinsic distribution of astrometric quantities, accounting for the full covariance matrix of the errors; this allows open cluster members to be identified even when presented with relatively uncertain measurement data. To date, open cluster studies have only applied extreme deconvolution to specialized searches for individual systems. We use XDGMM to characterize the open clusters reported by Ahumada et al. 2007 and are able to recover 420 of the 426 open clusters therein (98.1\textbackslash\%). Our membership list contains the overwhelming majority (\${$>$}95\textbackslash\%\$) of previously known cluster members. We also identify a new, significant, and relatively faint cluster member population and validate their membership status using Gaia eDR3. We report the fortuitous discovery of 11 new open cluster candidates within the lines of sight we analyzed. We present our technique, its advantages and challenges, as well as publish our membership lists and updated cluster parameters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6WU9LR6Z\\2108.html}}
@misc{jeff_reback_pandas-devpandas_2020, title = {Pandas-Dev/Pandas: {{Pandas}} 1.0.3}, shorttitle = {Pandas-Dev/Pandas}, author = {Jeff Reback and Wes McKinney and {jbrockmendel} and {Joris Van den Bossche} and Tom Augspurger and Phillip Cloud and {gfyoung} and Sinhrks and Adam Klein and Matthew Roeschke and Simon Hawkins and Jeff Tratner and Chang She and William Ayd and Terji Petersen and Marc Garcia and Jeremy Schendel and Andy Hayden and MomIsBestFriend and Vytautas Jancauskas and Pietro Battiston and Skipper Seabold and {chris-b1} and {h-vetinari} and Stephan Hoyer and Wouter Overmeire and {alimcmaster1} and Kaiqi Dong and Christopher Whelan and Mortada Mehyar}, year = {2020}, month = mar, doi = {10.5281/zenodo.3715232}, urldate = {2020-06-24}, abstract = {This is a minor bug-fix release in the 1.0.x series and includes some regression fixes and bug fixes. We recommend that all users upgrade to this version. See the full whatsnew for a list of all the changes. The release will be available on the defaults and conda-forge channels: conda install pandas Or via PyPI: python3 -m pip install --upgrade pandas Please report any issues with the release on the pandas issue tracker.}, howpublished = {Zenodo}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NFHNM5WC\\3715232.html}}
@article{jerabkova_800_pc_2021, title = {The 800 Pc Long Tidal Tails of the {{Hyades}} Star Cluster. {{Possible}} Discovery of Candidate Epicyclic Overdensities from an Open Star Cluster}, author = {Jerabkova, Tereza and Boffin, Henri M. J. and Beccari, Giacomo and {de Marchi}, Guido and {de Bruijne}, Jos H. J. and Prusti, Timo}, year = {2021}, month = mar, volume = {647}, eprint = {2103.12080}, primaryclass = {astro-ph.GA}, pages = {A137}, doi = {10.1051/0004-6361/202039949}, archiveprefix = {arxiv}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,ISM: clouds,open clusters and associations: general,open clusters and associations: individual: Hyades,solar neighborhood,stars: kinematics and dynamics}}
@article{johnston_dynamical_2019, title = {A {{Dynamical Systems Description}} of {{Privilege}}, {{Power}} and {{Leadership}} in {{Academia}}: Identifying Barriers and Paths to Inclusive Communities of Excellent Scholarship}, shorttitle = {A {{Dynamical Systems Description}} of {{Privilege}}, {{Power}} and {{Leadership}} in {{Academia}}}, author = {Johnston, Kathryn V.}, year = {2019}, month = dec, journal = {Nature Astronomy}, volume = {3}, number = {12}, eprint = {1912.06605}, pages = {1060--1066}, issn = {2397-3366}, doi = {10.1038/s41550-019-0961-2}, urldate = {2020-01-02}, abstract = {As the diversity of people in higher education grows, Universities are struggling to provide inclusive environments that nurture the spirit of free inquiry in the presence of these differences. At the extreme, the value of diversity is under attack as a few, vocal academics use public forums to question the innate intellectual abilities of certain demographic groups. Throughout my career as an astronomer, from graduate student, through professor to department chair, I have witnessed these struggles firsthand. Exclusive cultures result in lost opportunities in the form of unfulfilled potential of all members of the institution - students, administrators and faculty alike. How to move steadily towards inclusion is an unsolved problem that hampers the advancement of knowledge itself. As every scientist knows, problem definition is an essential feature of problem solution. This article draws on insights from dynamical systems descriptions of conflict developed in the social and behavioral sciences to present a model that captures the convoluted, interacting challenges that stifle progress on this problem. This description of complexity explains the persistence of exclusive cultures and the inadequacy of quick or simple fixes. It also motivates the necessity of prolonged and multifaceted approaches to solutions. It is incumbent on our faculties to recognize the complexities in both problem and solutions, and persevere in responding to these intractable dynamics. It is incumbent on our administrations to provide the consistent structure that supports these tasks. It incumbent on all of our constituents - students, administration and faculty - to be cognizant of and responsive to these efforts.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Physics - Physics and Society,Physics - Physics Education}}
@article{joshi_study_2016, title = {Study of Open Clusters within 1.8 Kpc and Understanding the {{Galactic}} Structure}, author = {Joshi, Y. C. and Dambis, A. K. and Pandey, A. K. and Joshi, S.}, year = {2016}, month = sep, journal = {Astronomy \& Astrophysics}, volume = {593}, pages = {A116}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201628944}, urldate = {2019-09-03}, abstract = {\emph{Context. {$<$}i/{$>$}Significant progress has been made in recent years to understand the formation and evolution of our Galaxy, but we still lack a complete understanding of the Galaxy and its structure.\emph{Aims. {$<$}i/{$>$}Using an almost complete sample of Galactic open star clusters within 1.8 kpc, we aim to understand the general properties of the open cluster system in the Galaxy and probe the Galactic structure.\emph{Methods. {$<$}i/{$>$}We first extracted 1241 open clusters within 1.8 kpc of the Sun from the Milky Way Star Clusters (MWSC) catalog. Considering it an almost complete sample of clusters within this distance, we performed a comprehensive statistical analysis of various cluster parameters such as spatial position, age, size, mass, and extinction.\emph{Results. {$<$}i/{$>$}We find an average cluster scale height of \emph{z{$<$}i/{$>$}\textsubscript{h{$<$}sub/{$>$} = 60 {$\pm$} 2 pc for clusters younger than 700 Myr, which increases to 64 {$\pm$} 2 pc when we include all the clusters. The \emph{z{$<$}i/{$>$}\textsubscript{h{$<$}sub/{$>$} is found to be strongly dependent on \emph{R{$<$}i/{$>$}\textsubscript{GC{$<$}sub/{$>$} and age, and on an average, \emph{z{$<$}i/{$>$}\textsubscript{h{$<$}sub/{$>$} is more than twice as large as in the outer region than in the inner region of the solar circle, except for the youngest population of clusters. The solar offset is found to be 6.2 {$\pm$} 1.1 pc above the formal Galactic plane. We derive a local mass density of \emph{{$\rho<$}i/{$>$}\textsubscript{0{$<$}sub/{$>$} = 0.090 {$\pm$} 0.005 \emph{M{$<$}i/{$>$}\textsubscript{{$\odot<$}sub/{$>$}/ pc\textsuperscript{3{$<$}sup/{$>$} and estimate a negligibly small amount of dark matter in the solar neighborhood. The reddening in the direction of clusters suggests a strong correlation with their vertical distance from the Galactic plane with a respective slope of d\emph{E{$<$}i/{$>$}(\emph{B{$<$}i/{$>-$}\emph{V{$<$}i/{$>$}) / d\emph{z{$<$}i/{$>$} = 0.40 {$\pm$} 0.04 and 0.42 {$\pm$} 0.05 mag/kpc below and above the Galactic plane. We observe a linear mass-radius and mass-age relations in the open clusters and derive the slopes of d\emph{R{$<$}i/{$>$}/ d(log \emph{M{$<$}i/{$>$}) = 2.08 {$\pm$} 0.10 and d(log \emph{M{$<$}i/{$>$}) / d(log \emph{T{$<$}i/{$>$}) = -0.36 {$\pm$} 0.05, respectively.\emph{Conclusions. {$<$}i/{$>$}The dependence of the spatial distribution of clusters on their age points to a complex interplay between cluster formation and survivability within the Galaxy. The geometrical characteristics of a significant number of clusters enabled us to understand large-scale spatial properties of the cluster systems within the Galaxy. The structural and physical parameters of clusters allowed us to check mutual correlations between the individual parameters.}}}}}}}}}}}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO, 2016}, langid = {english}, keywords = {\_tablet}, file = {C\:\\Users\\Emily\\Zotero\\storage\\T52MXQR2\\Joshi et al_2016_Study of open clusters within 1.pdf;C\:\\Users\\Emily\\Zotero\\storage\\T9HASSHH\\aa28944-16.html}}
@article{jospin_hands-bayesian_2022, title = {Hands-on {{Bayesian Neural Networks}} -- a {{Tutorial}} for {{Deep Learning Users}}}, author = {Jospin, Laurent Valentin and Buntine, Wray and Boussaid, Farid and Laga, Hamid and Bennamoun, Mohammed}, year = {2022}, month = jan, journal = {arXiv e-prints}, volume = {arXiv:2007.06823}, urldate = {2022-03-31}, abstract = {Modern deep learning methods constitute incredibly powerful tools to tackle a myriad of challenging problems. However, since deep learning methods operate as black boxes, the uncertainty associated with their predictions is often challenging to quantify. Bayesian statistics offer a formalism to understand and quantify the uncertainty associated with deep neural network predictions. This tutorial provides an overview of the relevant literature and a complete toolset to design, implement, train, use and evaluate Bayesian Neural Networks, i.e. Stochastic Artificial Neural Networks trained using Bayesian methods.}, keywords = {62-02 (Primary),Computer Science - Machine Learning,G.3,I.2.6,Statistics - Machine Learning}}
@article{just_global_survey_2023, title = {Global Survey of Star Clusters in the {{Milky Way}}. {{VII}}. {{Tidal}} Parameters and Mass Function}, author = {Just, A. and Piskunov, A. E. and Klos, J. H. and Kovaleva, D. A. and Polyachenko, E. V.}, year = {2023}, month = apr, journal = {Astronomy and Astrophysics}, volume = {672}, pages = {A187}, issn = {0004-6361}, doi = {10.1051/0004-6361/202244723}, urldate = {2023-05-01}, abstract = {Aims: We built Galactic open star cluster mass functions (CMFs) for different age sub-samples and spatial locations in the wider solar neighbourhood. Here, we present a simple cluster formation and evolution model to reproduce the main features of the CMFs. Methods: We used an unbiased working sample of 2227 clusters of the Milky Way Star Cluster (MWSC) catalogue, which occupy the heliocentric cylinders with magnitude-dependent completeness radii of 1-5 kpc. The MWSC survey provides an extended set of open star cluster parameters, including tidal radii, distances, and ages. From an analytic three-component Galaxy model, we derived tidal masses of clusters with a typical accuracy of about 70\%. Our simple model includes a two-section cluster initial mass function, constant cluster formation rate, supervirial phase after a sudden expulsion of the remaining gas, and cluster mass loss due to stellar evolution and the clusters' gradual destruction in the Galactic tidal field. The dynamical evolution model is based on previous N-body simulations. Results: The obtained tidal masses have been added to the MWSC catalogue. A general CMF (GCMF), built for all cluster ages around the Sun, has a bell-like shape and extends over four decades in mass. The high-mass slope found for tidal mass log mt/M{$\odot$} {$\geq$} 2.3 is equal to 1.14 {$\pm$} 0.07. The CMFs for different age groups show the same high-mass slopes, while the low-mass slope is nearly flat for the youngest sub-sample (clusters younger than 20 Myr) and about -0.7 for the others. The inner and outer sub-samples covering Galactocentric radii R = 4.2-8.1 kpc and 8.9-13.5 kpc, respectively, are consistent with the GCMF, once the exponential decline of the Galactic disc density is taken into account. The model suggests star formation with low efficiency of 15-20\%, where only 10\% of stars remain bound in a cluster after gas expulsion and subsequent violent relaxation. The cluster formation rate required to reproduce the observed distributions in age and mass is about 0.4 M{$\odot$} pc-2 Gyr-1. Conclusions: The obtained high-mass slope of the GCMF for the wide neighbourhood of the Sun is similar to slopes determined earlier in nearby galaxies for more luminous clusters with log m/M{$\odot$} {$>$} 3.8. The MWSC catalogue supports models with a low star-formation efficiency, where 90\% of stars are lost quickly after gas expulsion. The obtained cluster formation rate corresponds to open clusters' contribution to the stellar content of the thin disc at the level of 30\%.}, keywords = {Astrophysics - Astrophysics of Galaxies,galaxies: fundamental parameters,galaxies: photometry,galaxies: star clusters: general,Galaxy: evolution,Galaxy: stellar content,open clusters and associations: general}, annotation = {ADS Bibcode: 2023A\&A...672A.187J}}
@article{kamann_exploring_2021, title = {Exploring the Role of Binarity in the Origin of the Bimodal Rotational Velocity Distribution in Stellar Clusters}, author = {Kamann, S. and Bastian, N. and Usher, C. and {Cabrera-Ziri}, I. and Saracino, S.}, year = {2021}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2109.06947}, pages = {stab2643}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stab2643}, urldate = {2021-09-29}, abstract = {Many young and intermediate age massive stellar clusters host bimodal distributions in the rotation rates of their stellar populations, with a dominant peak of rapidly rotating stars and a secondary peak of slow rotators. The origin of this bimodal rotational distribution is currently debated and two main theories have been put forward in the literature. The first is that all/most stars are born as rapid rotators and that interacting binaries brake a fraction of the stars, resulting in two populations. The second is that the rotational distribution is a reflection of the early evolution of pre-main sequence stars, in particular, whether they are able to retain or lose their protoplanetary discs during the first few Myr. Here, we test the binary channel by exploiting multi-epoch VLT/MUSE observations of NGC 1850, a 100Myr massive cluster in the LMC, to search for differences in the binary fractions of the slow and fast rotating populations. If binarity is the cause of the rotational bimodality, we would expect that the slowly rotating population should have a much larger binary fraction than the rapid rotators. However, in our data we detect similar fractions of binary stars in the slow and rapidly rotating populations (5.9+/-1.1\% and 4.5+/-0.6\%, respectively).Hence, we conclude that binarity is not a dominant mechanism in the formation of the observed bimodal rotational distributions.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NSWBVLE9\\2109.html}}
@article{kamdar_spatial_2020, title = {Spatial and {{Kinematic Clustering}} of {{Stars}} in the {{Galactic Disk}}}, author = {Kamdar, Harshil and Conroy, Charlie and Ting, Yuan-Sen and {El-Badry}, Kareem}, year = {2020}, month = jul, journal = {arXiv:2007.10990 [astro-ph]}, eprint = {2007.10990}, primaryclass = {astro-ph}, urldate = {2020-07-23}, abstract = {The Galactic disk is expected to be spatially, kinematically, and chemically clustered on many scales due to both star formation and non-axisymmetries in the Galactic potential. In this work we calculate the spatial and kinematic two-point correlation functions using a sample of \$1.7 \textbackslash times 10\^6\$ stars within 1 kpc of the Sun with 6D phase space information available from \textbackslash textit\{Gaia\} DR2. Clustering is detected on spatial scales of 1-300 pc and velocity scales of at least 15 km s\$\^\{-1\}\$. With bound structures included, the data have a power-law index (\$\textbackslash xi(\textbackslash Delta r) \textbackslash propto \textbackslash Delta r\^\{\textbackslash gamma\}\$) of \$\textbackslash gamma\textbackslash approx-2\$ at most spatial scales, which is in line with theoretical predictions. After removing bound structures, the data have a power-law index of \$\textbackslash gamma\textbackslash approx-1\$ for \${$<$}100\$ pc and \$\textbackslash gamma \textbackslash lesssim -1.5\$ for \${$>$}100\$ pc. We interpret these results with the aid of a novel star-by-star simulation of the Galaxy in which stars are born in clusters orbiting in a realistic potential that includes spiral arms, a bar, and GMCs. We find that the simulation largely agrees with the observations (within a factor of 2-3) at all spatial and kinematic scales. In detail, the correlation function in the simulation is shallower than the data at \${$<$} 20\$ pc scales, and steeper than the data at \${$>$} 30\$ pc scales. We also find a persistent clustering signal in the kinematic correlation function for the data at large \$\textbackslash Delta v\$ (\${$>$}5\$ km s\$\^\{-1\}\$) not present in the simulations. We speculate that this mismatch between observations and simulations may be due to two processes not included in the simulation: hierarchical star formation and transient spiral arms. We also use the simulations to predict the clustering signal as a function of pair-wise metallicity and age separations. Ages and metallicities measured with a precision of \$50\textbackslash\%\$ and \$0.05\$ dex are required in order to enhance the clustering signal.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\DTAMYBQV\\2007.html}}
@misc{karam_modelling_star_2023, title = {Modelling {{Star Cluster Formation}}: {{Gas Accretion}}}, shorttitle = {Modelling {{Star Cluster Formation}}}, author = {Karam, Jeremy and Sills, Alison}, year = {2023}, month = mar, number = {arXiv:2303.11168}, eprint = {2303.11168}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.11168}, urldate = {2023-03-22}, abstract = {The formation of star clusters involves the growth of smaller, gas-rich subclusters through accretion of gas from the giant molecular cloud within which the subclusters are embedded. The two main accretion mechanisms responsible for this are accretion of gas from dense filaments, and from the ambient background of the cloud. We perform simulations of both of these accretion processes onto gas-rich star clusters using coupled smoothed particle hydrodynamics to model the gas, and N-body dynamics to model the stars. We find that, for both accretion processes, the accreting star cluster loses some of its original mass while gaining mass from either the ambient background or the dense filament. The amount of mass lost from both these processes is small compared to the total mass of the cluster. However, in the case of accretion from a background medium, the net effect can be a decrease in the total mass of the cluster if it is travelling fast enough through the ambient medium (\${$>$} 4\$kms\$\^\{-1\}\$). We find that the amount of mass lost from the cluster through filamentary accretion is independent of the density, width, or number of filaments funneling gas into the cluster and is always such that the mass of the cluster is constantly increasing with time. We compare our results to idealized prescriptions used to model star cluster formation in larger scale GMC simulations and find that such prescriptions act as an upper limit when describing the mass of the star cluster they represent.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@misc{karatas_study_2023, title = {Study of the {{Open Clusters}} in {{Kepler Prime Field}}}, author = {Karata{\c s}, Y{\"u}ksel and {\c C}akmak, Hikmet and Oralhan, {\.I}nci Akkaya and Bonatto, Charles and Michel, Ra{\'u}l and Netopil, Martin}, year = {2023}, month = feb, number = {arXiv:2302.09851}, eprint = {2302.09851}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2302.09851}, urldate = {2023-02-21}, abstract = {We present a detailed study of NGC 6791, NGC 6811, NGC 6819 and NGC 6866, the four open clusters that are located in the Kepler prime field. We use new CCD UBV(RI)KC photometry, which was combined with Gaia EDR3 photometric/astrometric data, to derive the astrophysical parameters with two independent methods - one of them the fitCMD algorithm. Furthermore, we provide among others estimates of the mass and mass function, the cluster structure, derive the cluster orbits, and discuss the cluster dynamics. All objects belong to the older open cluster population (1-7Gyr), are in an advanced dynamical stage with signs of mass segregation, and are located close to the solar circle, but show a large range in respect of radii, member stars or observed cluster mass (100-2000 Msolar). For the three younger objects we were also able to provide photometric metallicity estimates, which confirms their status as clusters with a roughly solar metallicity. The most outstanding object is clearly NGC 6791, a very old cluster with a high metallicity at a distance of about 4.5 kpc from the Sun. We estimate a probable radial migration by about 7 kpc, resulting in a birth position close to the Galactic center.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@misc{katz_gaia_2022, title = {Gaia {{Data Release}} 3 {{Properties}} and Validation of the Radial Velocities}, author = {Katz, D. and Sartoretti, P. and Guerrier, A. and Panuzzo, P. and Seabroke, G. M. and Th{\'e}venin, F. and Cropper, M. and Benson, K. and Blomme, R. and Haigron, R. and Marchal, O. and Smith, M. and Baker, S. and Chemin, L. and Damerdji, Y. and David, M. and Dolding, C. and Fr{\'e}mat, Y. and Gosset, E. and Jan{\ss}en, K. and Jasniewicz, G. and Lobel, A. and Plum, G. and Samaras, N. and Snaith, O. and Soubiran, C. and Vanel, O. and Zwitter, T. and Antoja, T. and Arenou, F. and Babusiaux, C. and Brouillet, N. and Caffau, E. and Di Matteo, P. and Fabre, C. and Fabricius, C. and Frakgoudi, F. and Haywood, M. and Huckle, H. E. and Hottier, C. and Lasne, Y. and Leclerc, N. and {Mastrobuono-Battisti}, A. and Royer, F. and Teyssier, D. and Zorec, J. and Crifo, F. and {Jean-Antoine Piccolo}, A. and Turon, C. and Viala, Y.}, year = {2022}, month = jun, journal = {arXiv e-prints}, urldate = {2023-01-19}, abstract = {Gaia Data Release 3 (Gaia DR3) contains the second release of the combined radial velocities. It is based on the spectra collected during the first 34 months of the nominal mission. The longer time baseline and the improvements of the pipeline made it possible to push the processing limit, from Grvs = 12 in Gaia DR2, to Grvs = 14 mag. In this article, we describe the new functionalities implemented for Gaia DR3, the quality filters applied during processing and post-processing and the properties and performance of the published velocities. For Gaia DR3, several functionalities were upgraded or added. (Abridged) Gaia DR3 contains the combined radial velocities of 33 812 183 stars. With respect to Gaia DR2, the interval of temperature has been expanded from Teff \textbackslash in [3600, 6750] K to Teff \textbackslash in [3100, 14500] K for the bright stars ( Grvs \textbackslash leq 12 mag) and [3100, 6750] K for the fainter stars. The radial velocities sample a significant part of the Milky Way: they reach a few kilo-parsecs beyond the Galactic centre in the disc and up to about 10-15 kpc vertically into the inner halo. The median formal precision of the velocities is of 1.3 km/s at Grvs = 12 and 6.4 km/s at Grvs = 14 mag. The velocity zero point exhibits a small systematic trend with magnitude starting around Grvs = 11 mag and reaching about 400 m/s at Grvs = 14 mag. A correction formula is provided, which can be applied to the published data. The Gaia DR3 velocity scale is in satisfactory agreement with APOGEE, GALAH, GES and RAVE, with systematic differences that mostly do not exceed a few hundreds m/s. The properties of the radial velocities are also illustrated with specific objects: open clusters, globular clusters as well as the Large Magellanic Cloud (LMC). For example, the precision of the data allows to map the line-of-sight rotational velocities of the globular cluster 47 Tuc and of the LMC.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, annotation = {ADS Bibcode: 2022arXiv220605902K}}
@article{kaya_deep_2019, title = {Deep {{Metric Learning}}: {{A Survey}}}, shorttitle = {Deep {{Metric Learning}}}, author = {Kaya, Mahmut and B{\.i}lge, Hasan {\c S}akir}, year = {2019}, month = sep, journal = {Symmetry}, volume = {11}, number = {9}, pages = {1066}, doi = {10.3390/sym11091066}, urldate = {2020-02-06}, abstract = {Metric learning aims to measure the similarity among samples while using an optimal distance metric for learning tasks. Metric learning methods, which generally use a linear projection, are limited in solving real-world problems demonstrating non-linear characteristics. Kernel approaches are utilized in metric learning to address this problem. In recent years, deep metric learning, which provides a better solution for nonlinear data through activation functions, has attracted researchers\’ attention in many different areas. This article aims to reveal the importance of deep metric learning and the problems dealt with in this field in the light of recent studies. As far as the research conducted in this field are concerned, most existing studies that are inspired by Siamese and Triplet networks are commonly used to correlate among samples while using shared weights in deep metric learning. The success of these networks is based on their capacity to understand the similarity relationship among samples. Moreover, sampling strategy, appropriate distance metric, and the structure of the network are the challenging factors for researchers to improve the performance of the network model. This article is considered to be important, as it is the first comprehensive study in which these factors are systematically analyzed and evaluated as a whole and supported by comparing the quantitative results of the methods.}, copyright = {http://creativecommons.org/licenses/by/3.0/}, langid = {english}, keywords = {deep metric learning,metric learning,siamese network,similarity,triplet network}, file = {C\:\\Users\\Emily\\Zotero\\storage\\3JLRGXTF\\htm.html}}
@article{keller_where_2020, title = {Where Did the Globular Clusters of the {{Milky Way}} Form? {{Insights}} from the {{E-MOSAICS}} Simulations}, shorttitle = {Where Did the Globular Clusters of the {{Milky Way}} Form?}, author = {Keller, Benjamin W. and Kruijssen, J. M. Diederik and Pfeffer, Joel and {Reina-Campos}, Marta and Bastian, Nate and {Trujillo-Gomez}, Sebastian and Hughes, Meghan E. and Crain, Robert A.}, year = {2020}, month = may, journal = {arXiv:2005.05342 [astro-ph]}, eprint = {2005.05342}, primaryclass = {astro-ph}, urldate = {2020-05-13}, abstract = {Globular clusters (GCs) are typically old, with most having formed at z {$>\sptilde$} 2. This makes understanding their birth environments difficult, as they are typically too distant to observe with sufficient angular resolution to resolve GC birth sites. Using 25 cosmological zoom-in simulations of Milky Way-like galaxies from the E-MOSAICS project, with physically-motivated models for star formation, feedback, and the formation, evolution, and disruption of GCs, we identify the birth environments of present-day GCs. We find roughly half of GCs in these galaxies formed in-situ (52.0 +/- 1.0 per cent) between z \textasciitilde{} 2 - 4, in turbulent, high-pressure discs fed by gas that was accreted without ever being strongly heated through a virial shock or feedback. A minority of GCs form during mergers (12.6 +/- 0.6 per cent in major mergers, and 7.2 +/- 0.5 per cent in minor mergers), but we find that mergers are important for preserving the GCs seen today by ejecting them from their natal, high density interstellar medium (ISM), where proto-GCs are rapidly destroyed due to tidal shocks from ISM substructure. This chaotic history of hierarchical galaxy assembly acts to mix the spatial and kinematic distribution of GCs formed through different channels, making it difficult to use observable GC properties to distinguish GCs formed in mergers from ones formed by smooth accretion, and similarly GCs formed in-situ from those formed ex-situ. These results suggest a simple picture of GC formation, in which GCs are a natural outcome of normal star formation in the typical, gas-rich galaxies that are the progenitors of present-day galaxies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\G5D4I54B\\2005.html}}
@article{kerr_stars_2021, title = {Stars with {{Photometrically Young Gaia Luminosities Around}} the {{Solar System}} ({{SPYGLASS}}) {{I}}: {{Mapping Young Stellar Structures}} and Their {{Star Formation Histories}}}, shorttitle = {Stars with {{Photometrically Young Gaia Luminosities Around}} the {{Solar System}} ({{SPYGLASS}}) {{I}}}, author = {Kerr, Ronan and Rizzuto, Aaron C. and Kraus, Adam L. and Offner, Stella S. R.}, year = {2021}, month = may, journal = {arXiv:2105.09338 [astro-ph]}, eprint = {2105.09338}, primaryclass = {astro-ph}, urldate = {2021-06-07}, abstract = {Young stellar associations hold a star formation record that can persist for millions of years, revealing the progression of star formation long after the dispersal of the natal cloud. To identify nearby young stellar populations that trace this progression, we have designed a comprehensive framework for the identification of young stars, and use it to identify \$\textbackslash sim\$3\$\textbackslash times 10\^4\$ candidate young stars within a distance of 333 pc using Gaia DR2. Applying the HDBSCAN clustering algorithm to this sample, we identify 27 top-level groups, nearly half of which have little to no presence in previous literature. Ten of these groups have visible substructure, including notable young associations such as Orion, Perseus, Taurus, and Sco-Cen. We provide a complete subclustering analysis on all groups with substructure, using age estimates to reveal each region's star formation history. The patterns we reveal include an apparent star formation origin for Sco-Cen along a semicircular arc, as well as clear evidence for sequential star formation moving away from that arc with a propagation speed of \$\textbackslash sim\$4 km s\$\^\{-1\}\$ (\$\textbackslash sim\$4 pc Myr\$\^\{-1\}\$). We also identify earlier bursts of star formation in Perseus and Taurus that predate current, kinematically identical active star-forming events, suggesting that the mechanisms that collect gas can spark multiple generations of star formation, punctuated by gas dispersal and cloud regrowth. The large spatial scales and long temporal scales on which we observe star formation offer a bridge between the processes within individual molecular clouds and the broad forces guiding star formation at galactic scales.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QDPNGWHF\\2105.html}}
@article{kervella_stellar_substellar_2019, title = {Stellar and Substellar Companions of Nearby Stars from {{Gaia DR2}}. {{Binarity}} from Proper Motion Anomaly}, author = {Kervella, Pierre and Arenou, Fr{\'e}d{\'e}ric and Mignard, Fran{\c c}ois and Th{\'e}venin, Fr{\'e}d{\'e}ric}, year = {2019}, month = mar, journal = {Astronomy and Astrophysics}, volume = {623}, pages = {A72}, issn = {0004-6361}, doi = {10.1051/0004-6361/201834371}, urldate = {2023-04-27}, abstract = {Context. The census of stellar and substellar companions of nearby stars is largely incomplete, in particular toward the low-mass brown dwarf and long-period exoplanets. It is, however, fundamentally important in the understanding of the stellar and planetary formation and evolution mechanisms. Nearby stars are particularly favorable targets for high precision astrometry. Aims: We aim to characterize the presence of physical companions of stellar and substellar mass in orbit around nearby stars. Methods: Orbiting secondary bodies influence the proper motion of their parent star through their gravitational reflex motion. Using the HIPPARCOS and Gaia's second data release (GDR2) catalogs, we determined the long-term proper motion of the stars common to these two catalogs. We then searched for a proper motion anomaly (PMa) between the long-term proper motion vector and the GDR2 (or HIPPARCOS) measurements, indicative of the presence of a perturbing secondary object. We focussed our analysis on the 6741 nearby stars located within 50 pc, and we also present a catalog of the PMa for {$\greaterequivlnt$}99\% of the HIPPARCOS catalog ({$\approx$}117 000 stars). Results: 30\% of the stars studied present a PMa greater than 3{$\sigma$}. The PMa allows us to detect orbiting companions, or set stringent limits on their presence. We present a few illustrations of the PMa analysis to interesting targets. We set upper limits of 0.1-0.3 MJ to potential planets orbiting Proxima between 1 and 10 au (Porb = 3 to 100 years). We confirm that Proxima is gravitationally bound to {$\alpha$} Cen. We recover the masses of the known companions of {$\varepsilon$} Eri, {$\varepsilon$} Ind, Ross 614 and {$\beta$} Pic. We also detect the signature of a possible planet of a few Jovian masses orbiting {$\tau$} Ceti. Conclusions: Based on only 22 months of data, the GDR2 has limitations. But its combination with the HIPPARCOS catalog results in very high accuracy PMa vectors, that already enable us to set valuable constraints on the binarity of nearby objects. The detection of tangential velocity anomalies at a median accuracy of {$\sigma$}({$\Delta$}vT) = 1.0 m s-1 per parsec of distance is already possible with the GDR2. This type of analysis opens the possibility to identify long period orbital companions otherwise inaccessible. For long orbital periods, Gaia's complementarity to radial velocity and transit techniques (that are more sensitive to short orbital periods) already appears to be remarkably powerful. Full Tables 1 and 2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/623/A72}, keywords = {astrometry,Astrophysics - Solar and Stellar Astrophysics,binaries: general,planetary systems,proper motions}, annotation = {ADS Bibcode: 2019A\&A...623A..72K}}
@article{kharchenko_allsky_compiled_2001, title = {All-Sky Compiled Catalogue of 2.5 Million Stars}, author = {Kharchenko, N. V.}, year = {2001}, month = oct, journal = {Kinematika i Fizika Nebesnykh Tel}, volume = {17}, pages = {409--423}, issn = {0233-7665}, urldate = {2023-04-27}, abstract = {The all-sky Compiled Catalogue of more than 2.5 million stars with the limiting magnitude V {$\approx$}14(m) was created as a result of combining of star lists from present-day large high-precision catalogues of space (HIPPARCOS Tycho family catalogues) and ground-based (PPM, CMC11) observations and reducing them to the standard systems of corresponding stellar data. The main stellar data presented in the Compiled Catalogue are the equatorial coordinates (J2000, epoch 1991.25), proper motions in the HIPPARCOS system and space B, V stellar magnitudes in the Johnson system. Trigonometric parallaxes, spectral classes in the MK or HD system, multiplicity and variability flags are also given for some stars. A review of the high-precision large catalogues is also provided.}, annotation = {ADS Bibcode: 2001KFNT...17..409K}}
@article{kharchenko_global_2012, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{I}}. {{The}} Pipeline and Fundamental Parameters in the Second Quadrant}, author = {Kharchenko, N. V. and Piskunov, A. E. and Schilbach, E. and R{\"o}ser, S. and Scholz, R.-D.}, year = {2012}, month = jul, journal = {Astronomy \& Astrophysics}, volume = {543}, pages = {A156}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201118708}, urldate = {2019-09-03}, abstract = {\emph{Aims.{$<$}i/{$>$} On the basis of the PPMXL star catalogue we performed a survey of star clusters in the second quadrant of the Milky Way.\emph{Methods.{$<$}i/{$>$} From the PPMXL catalogue of positions and proper motions we took the subset of stars with near-infrared photometry from 2MASS and added the remaining 2MASS stars without proper motions (called 2MAst, i.e. 2MASS with astrometry). We developed a data-processing pipeline including interactive human control of a standardised set of multi-dimensional diagrams to determine kinematic and photometric membership probabilities for stars in a cluster region. The pipeline simultaneously produced the astrophysical parameters of a cluster. From literature we compiled a target list of presently known open and globular clusters, cluster candidates, associations, and moving groups. From established member stars we derived spatial parameters (coordinates of centres and radii of the main morphological parts of clusters) and cluster kinematics (average proper motions and sometimes radial velocities). For distance, reddening, and age determination we used specific sets of theoretical isochrones. Tidal parameters were obtained by a fit of three-parameter King profiles to the observed density distributions of members.\emph{Results.{$<$}i/{$>$} We investigated all 871 objects in the 2nd Galactic quadrant, of which we successfully treated 642 open clusters, 2 globular clusters, and 8 stellar associations. The remaining 219 objects (24\%) were recognised by us to be nonexistent clusters, duplicate entries, or clusters too faint for 2MAst. We found that our sample is complete in the 2nd quadrant up to a distance of 2 kpc, where the average surface density is 94 clusters per kpc\textsuperscript{2{$<$}sup/{$>$}. Compared with literature values we found good agreement in spatial and kinematic data, as well as for optical distances and reddening. Small, but systematic offsets were detected in the age determination.}}}}}, copyright = {\textcopyright{} ESO, 2012}, langid = {english}, keywords = {Catalogue: MWSC,OC Analysis,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HINP57KF\\Kharchenko et al. - 2012 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\J7SKP5TI\\aa18708-11.html}}
@article{kharchenko_global_2013, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{II}}. {{The}} Catalogue of Basic Parameters}, author = {Kharchenko, N. V. and Piskunov, A. E. and Schilbach, E. and R{\"o}ser, S. and Scholz, R.-D.}, year = {2013}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {558}, pages = {A53}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201322302}, urldate = {2019-09-03}, abstract = {\emph{Context. {$<$}i/{$>$}Although they are the main constituents of the Galactic disk population, for half of the open clusters in the Milky Way reported in the literature nothing is known except the raw position and an approximate size.\emph{Aims. {$<$}i/{$>$}The main goal of this study is to determine a full set of uniform spatial, structural, kinematic, and astrophysical parameters for as many known open clusters as possible.\emph{Methods. {$<$}i/{$>$}On the basis of stellar data from PPMXL and 2MASS, we used a dedicated data-processing pipeline to determine kinematic and photometric membership probabilities for stars in a cluster region.\emph{Results. {$<$}i/{$>$}For an input list of 3784 targets from the literature, we confirm that 3006 are real objects, the vast majority of them are open clusters, but associations and globular clusters are also present. For each confirmed object we determined the exact position of the cluster centre, the apparent size, proper motion, distance, colour excess, and age. For about 1500 clusters, these basic astrophysical parameters have been determined for the first time. For the bulk of the clusters we also derived the tidal radius. We estimated additionally average radial velocities for more than 30\% of the confirmed clusters. The present sample (called MWSC) reaches both the central parts of the Milky Way and its outer regions. It is almost complete up to 1.8 kpc from the Sun and also covers neighbouring spiral arms. However, for a small subset of the oldest open clusters (log \emph{t{$<$}i/{$>$} {$\greaterequivlnt$} 9) we found some evidence of incompleteness within about 1 kpc from the Sun.}}}}}}, copyright = {\textcopyright{} ESO, 2013}, langid = {english}, keywords = {Catalogue: MWSC,OC Analysis,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Q8CG3PQ7\\Kharchenko et al. - 2013 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\EZI7A7IE\\aa22302-13.html}}
@article{kharchenko_global_2016, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{V}}. {{Integrated JHKS}} Magnitudes and Luminosity Functions}, author = {Kharchenko, N. V. and Piskunov, A. E. and Schilbach, E. and R{\"o}ser, S. and Scholz, R.-D.}, year = {2016}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {585}, pages = {A101}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201527292}, urldate = {2019-09-03}, abstract = {\emph{Aims. {$<$}i/{$>$}In this study we determine absolute integrated magnitudes in the \emph{J,H,{$<$}i/{$>$}\emph{K{$<$}i/{$>$}\textsubscript{S{$<$}sub/{$>$} passbands for Galactic star clusters from the Milky Way Star Clusters survey. In the wide solar neighbourhood, we derive the open cluster luminosity function (CLF) for different cluster ages.\emph{Methods. {$<$}i/{$>$}The integrated magnitudes are based on uniform cluster membership derived from the 2MAst catalogue (a merger of the PPMXL and 2MASS) and are computed by summing up the individual luminosities of the most reliable cluster members. We discuss two different techniques of constructing the CLF, a magnitude-limited and a distance-limited approach.\emph{Results. {$<$}i/{$>$}Absolute \emph{J,H,{$<$}i/{$>$}\emph{K{$<$}i/{$>$}\textsubscript{S{$<$}sub/{$>$} integrated magnitudes are obtained for 3061 open clusters, and 147 globular clusters. The integrated magnitudes and colours are accurate to about 0.8 and 0.2 mag, respectively. Based on the sample of open clusters we construct the general cluster luminosity function in the solar neighbourhood in the three passbands. In each passband the CLF shows a linear part covering a range of 6 to 7 mag at the bright end. The CLFs reach their maxima at an absolute magnitude of -2 mag, then drop by one order of magnitude. During cluster evolution, the CLF changes its slope within tight, but well-defined limits. The CLF of the youngest clusters has a steep slope of about 0.4 at bright magnitudes and a quasi-flat portion for faint clusters. For the oldest population, we find a flatter function with a slope of about 0.2. The CLFs at Galactocentric radii smaller than that of the solar circle differ from those in the direction of the Galactic anti-centre. The CLF in the inner area is flatter and the cluster surface density higher than the local one. In contrast, the CLF is somewhat steeper than the local one in the outer disk, and the surface density is lower.}}}}}}}}}}, copyright = {\textcopyright{} ESO, 2015}, langid = {english}, keywords = {\_tablet\_modified,Catalogue: MWSC}, file = {C\:\\Users\\Emily\\Zotero\\storage\\588KX84A\\Kharchenko et al. - 2016 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\DFC2RHBM\\Kharchenko et al. - 2016 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\TG54Y5JR\\aa27292-15.html}}
@article{killestein_transient-optimised_2021, title = {Transient-Optimised Real-Bogus Classification with {{Bayesian Convolutional Neural Networks}} -- Sifting the {{GOTO}} Candidate Stream}, author = {Killestein, T. L. and Lyman, J. and Steeghs, D. and Ackley, K. and Dyer, M. J. and Ulaczyk, K. and Cutter, R. and Mong, Y.-L. and Galloway, D. K. and Dhillon, V. and O'Brien, P. and Ramsay, G. and Poshyachinda, S. and Kotak, R. and Breton, R. P. and Nuttall, L. K. and Pall{\'e}, E. and Pollacco, D. and Thrane, E. and Aukkaravittayapun, S. and Awiphan, S. and Burhanudin, U. and Chote, P. and Chrimes, A. and Daw, E. and Duffy, C. and {Eyles-Ferris}, R. and Gompertz, B. and Heikkil{\"a}, T. and Irawati, P. and Kennedy, M. R. and Levan, A. and Littlefair, S. and Makrygianni, L. and S{\'a}nchez, D. Mata and Mattila, S. and Maund, J. and McCormac, J. and Mkrtichian, D. and Mullaney, J. and Rol, E. and Sawangwit, U. and Stanway, E. and Starling, R. and Str{\o}m, P. A. and Tooke, S. and Wiersema, K. and Williams, S. C.}, year = {2021}, month = feb, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {503}, number = {4}, eprint = {2102.09892}, pages = {4838--4854}, urldate = {2021-02-24}, abstract = {Large-scale sky surveys have played a transformative role in our understanding of astrophysical transients, only made possible by increasingly powerful machine learning-based filtering to accurately sift through the vast quantities of incoming data generated. In this paper, we present a new real-bogus classifier based on a Bayesian convolutional neural network that provides nuanced, uncertainty-aware classification of transient candidates in difference imaging, and demonstrate its application to the datastream from the GOTO wide-field optical survey. Not only are candidates assigned a well-calibrated probability of being real, but also an associated confidence that can be used to prioritise human vetting efforts and inform future model optimisation via active learning. To fully realise the potential of this architecture, we present a fully-automated training set generation method which requires no human labelling, incorporating a novel data-driven augmentation method to significantly improve the recovery of faint and nuclear transient sources. We achieve competitive classification accuracy (FPR and FNR both below 1\%) compared against classifiers trained with fully human-labelled datasets, whilst being significantly quicker and less labour-intensive to build. This data-driven approach is uniquely scalable to the upcoming challenges and data needs of next-generation transient surveys. We make our data generation and model training codes available to the community.}, archiveprefix = {arxiv}, keywords = {Astrophysics - High Energy Astrophysical Phenomena,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\THITDS7R\\2102.html}}
@article{king_structure_1966, title = {The Structure of Star Clusters. {{III}}. {{Some}} Simple Dynamical Models}, author = {King, Ivan R.}, year = {1966}, month = feb, journal = {The Astronomical Journal}, volume = {71}, pages = {64}, issn = {0004-6256}, doi = {10.1086/109857}, urldate = {2022-07-25}, abstract = {Dynamical models of star clusters are presented, based on steady-state solutions of the Fokker-Planck equation. The models are spatially limited, corresponding to the tidal cutoff imposed by the Milky Way. Their projected density distributions are similar to those observed in open clusters, globular clusters, and elliptical galaxies. Within each model the fractional escape rate is uniform throughout. The escape rate from a cluster depends on the number of stars and the strength of the tidal force field; when expressed in this way it is almost independent of core radius or central concentration. Quantitative application to actual clusters must await a discussion of models containing a realistic stellar mixture.}, annotation = {ADS Bibcode: 1966AJ.....71...64K}}
@article{king_structure_star_1962, title = {The Structure of Star Clusters. {{I}}. an Empirical Density Law - {{NASA}}/{{ADS}}}, author = {King, Ivan}, year = {1962}, journal = {The Astronomical Journal}, volume = {67}, pages = {471}, urldate = {2019-11-21}, abstract = {A powerful, streamlined new Astrophysics Data System}, langid = {english}, keywords = {King Profile,radius,sc density profile,SC radii,sc structure}, file = {C\:\\Users\\Emily\\Zotero\\storage\\XPXNYZLR\\abstract.html}}
@article{kingma_adam_2017, title = {Adam: {{A Method}} for {{Stochastic Optimization}}}, shorttitle = {Adam}, author = {Kingma, Diederik P. and Ba, Jimmy}, year = {2017}, month = jan, journal = {arXiv e-prints}, volume = {arXiv:1412.6980}, urldate = {2022-04-04}, abstract = {We introduce Adam, an algorithm for first-order gradient-based optimization of stochastic objective functions, based on adaptive estimates of lower-order moments. The method is straightforward to implement, is computationally efficient, has little memory requirements, is invariant to diagonal rescaling of the gradients, and is well suited for problems that are large in terms of data and/or parameters. The method is also appropriate for non-stationary objectives and problems with very noisy and/or sparse gradients. The hyper-parameters have intuitive interpretations and typically require little tuning. Some connections to related algorithms, on which Adam was inspired, are discussed. We also analyze the theoretical convergence properties of the algorithm and provide a regret bound on the convergence rate that is comparable to the best known results under the online convex optimization framework. Empirical results demonstrate that Adam works well in practice and compares favorably to other stochastic optimization methods. Finally, we discuss AdaMax, a variant of Adam based on the infinity norm.}, keywords = {Computer Science - Machine Learning}}
@misc{kingma_auto-encoding_2022, title = {Auto-{{Encoding Variational Bayes}}}, author = {Kingma, Diederik P. and Welling, Max}, year = {2022}, month = dec, number = {arXiv:1312.6114}, eprint = {1312.6114}, primaryclass = {cs, stat}, publisher = {{arXiv}}, doi = {10.48550/arXiv.1312.6114}, urldate = {2022-12-19}, abstract = {How can we perform efficient inference and learning in directed probabilistic models, in the presence of continuous latent variables with intractable posterior distributions, and large datasets? We introduce a stochastic variational inference and learning algorithm that scales to large datasets and, under some mild differentiability conditions, even works in the intractable case. Our contributions are two-fold. First, we show that a reparameterization of the variational lower bound yields a lower bound estimator that can be straightforwardly optimized using standard stochastic gradient methods. Second, we show that for i.i.d. datasets with continuous latent variables per datapoint, posterior inference can be made especially efficient by fitting an approximate inference model (also called a recognition model) to the intractable posterior using the proposed lower bound estimator. Theoretical advantages are reflected in experimental results.}, archiveprefix = {arxiv}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{kingma_variational_2015, title = {Variational {{Dropout}} and the {{Local Reparameterization Trick}}}, author = {Kingma, Diederik P. and Salimans, Tim and Welling, Max}, year = {2015}, month = dec, journal = {arXiv:1506.02557 [cs, stat]}, eprint = {1506.02557}, primaryclass = {cs, stat}, urldate = {2022-03-31}, abstract = {We investigate a local reparameterizaton technique for greatly reducing the variance of stochastic gradients for variational Bayesian inference (SGVB) of a posterior over model parameters, while retaining parallelizability. This local reparameterization translates uncertainty about global parameters into local noise that is independent across datapoints in the minibatch. Such parameterizations can be trivially parallelized and have variance that is inversely proportional to the minibatch size, generally leading to much faster convergence. Additionally, we explore a connection with dropout: Gaussian dropout objectives correspond to SGVB with local reparameterization, a scale-invariant prior and proportionally fixed posterior variance. Our method allows inference of more flexibly parameterized posteriors; specifically, we propose variational dropout, a generalization of Gaussian dropout where the dropout rates are learned, often leading to better models. The method is demonstrated through several experiments.}, archiveprefix = {arxiv}, keywords = {Computer Science - Machine Learning,Statistics - Computation,Statistics - Machine Learning}}
@inproceedings{kluyver_jupyter_2016, title = {Jupyter {{Notebooks}} \textendash{} a Publishing Format for Reproducible Computational Workflows}, booktitle = {Positioning and {{Power}} in {{Academic Publishing}}: {{Players}}, {{Agents}} and {{Agendas}}}, author = {Kluyver, Thomas and {Ragan-Kelley}, Benjamin and P{\'e}rez, Fernando and Granger, Brian and Bussonnier, Matthias and Frederic, Jonathan and Kelley, Kyle and Hamrick, Jessica and Grout, Jason and Corlay, Sylvain and Ivanov, Paul and Avila, Dami{\'a}n and Abdalla, Safia and Willing, Carol}, editor = {Loizides, F. and Schmidt, B.}, year = {2016}, pages = {87--90}, publisher = {{IOS Press}}}
@article{kos_galah_2018, title = {The {{GALAH}} Survey and {{Gaia DR2}}: (Non-)Existence of Five Sparse High-Latitude Open Clusters}, shorttitle = {The {{GALAH}} Survey and {{Gaia DR2}}}, author = {Kos, Janez and {de Silva}, Gayandhi and Buder, Sven and {Bland-Hawthorn}, Joss and Sharma, Sanjib and Asplund, Martin and D'Orazi, Valentina and Duong, Ly and Freeman, Ken and Lewis, Geraint F. and Lin, Jane and Lind, Karin and Martell, Sarah L. and Schlesinger, Katharine J. and Simpson, Jeffrey D. and Zucker, Daniel B. and Zwitter, Toma{\v z} and Bedding, Timothy R. and {\v C}otar, Klemen and Horner, Jonathan and Nordlander, Thomas and Stello, Denis and Ting, Yuan-Sen and Traven, Gregor}, year = {2018}, month = nov, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {480}, number = {4}, pages = {5242}, doi = {10.1093/mnras/sty2171}, urldate = {2019-10-02}, abstract = {Sparse open clusters can be found at high galactic latitudes where loosely populated clusters are more easily detected against the lower stellar background. Because most star formation takes place in the thin disc, the observed population of clusters far from the Galactic plane is hard to explain. We combined spectral parameters from the GALAH survey with the Gaia DR2 catalogue to study the dynamics and chemistry of five old sparse high-latitude clusters in more detail. We find that four of them (NGC 1252, NGC 6994, NGC 7772, NGC 7826) - originally classified in 1888 - are not clusters but are instead chance projections on the sky. Member stars quoted in the literature for these four clusters are unrelated in our multidimensional physical parameter space; the quoted cluster properties in the literature are therefore meaningless. We confirm the existence of visually similar NGC 1901 for which we provide a probabilistic membership analysis. An overdensity in three spatial dimensions proves to be enough to reliably detect sparse clusters, but the whole six-dimensional space must be used to identify members with high confidence, as demonstrated in the case of NGC 1901.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\337E6ARJ\\abstract.html}}
@article{kounkel_untangling_2019, title = {Untangling the {{Galaxy}}. {{I}}. {{Local Structure}} and {{Star Formation History}} of the {{Milky Way}}}, author = {Kounkel, Marina and Covey, Kevin}, year = {2019}, month = aug, journal = {The Astronomical Journal}, volume = {158}, number = {3}, pages = {122}, issn = {1538-3881}, doi = {10.3847/1538-3881/ab339a}, urldate = {2019-10-21}, abstract = {Gaia DR2 provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and (many of which have not been previously known). We estimate their ages with the precision of {$\sim$}0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings ({$<$}100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of {$\sim$}300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.}, langid = {english}, keywords = {OC Analysis,OC Finder,Read}}
@article{kounkel_untangling_2020, title = {Untangling the {{Galaxy}}. {{II}}. {{Structure}} within 3 Kpc}, author = {Kounkel, Marina and Covey, Kevin and Stassun, Keivan G.}, year = {2020}, month = oct, journal = {The Astronomical Journal}, volume = {160}, number = {6}, eprint = {2004.07261}, pages = {279}, urldate = {2020-10-09}, abstract = {We present the results of the hierarchical clustering analysis of the Gaia DR2 data to search for clusters, co-moving groups, and other stellar structures. The current paper builds on the sample from the previous work, extending it in distance from 1 kpc to 3 kpc, increasing the number of identified structures up to 8292. To aid in the analysis of the population properties, we developed a neural network called Auriga to robustly estimate the age, extinction, and distance of a stellar group based on the input photometry and parallaxes of the individual members. We apply Auriga to derive the properties of not only the structures found in this paper, but also previously identified open clusters. Through this work, we examine the temporal structure of the spiral arms. Specifically, we find that the Sagittarius arm has moved by {$>$}500 pc in the last 100 Myr, and the Perseus arm has been experiencing a relative lull in star formation activity over the last 25 Myr. We confirm the findings from the previous paper on the transient nature of the spiral arms, with the timescale of transition of a few 100 Myr. Finally, we find a peculiar \textasciitilde 1 Gyr old stream of stars that appears to be heliocentric. It is unclear what is the origin of it.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QNNZ7YQC\\2004.html}}
@article{kovaleva_collinder_2020, title = {Collinder 135 and {{UBC}} 7: {{A Physical Pair}} of {{Open Clusters}}}, shorttitle = {Collinder 135 and {{UBC}} 7}, author = {Kovaleva, Dana and Ishchenko, Marina and Postnikova, Ekaterina and Berczik, Peter and Piskunov, Anatoly E. and Kharchenko, Nina V. and Polyachenko, Evgeny and Reffert, Sabine and Sysoliatina, Kseniia and Just, Andreas}, year = {2020}, month = sep, journal = {Astronomy \& Astrophysics}, volume = {642}, eprint = {2009.02223}, pages = {L4}, urldate = {2020-09-07}, abstract = {Given the closeness of the two open clusters Cr 135 and UBC 7 on the sky, we investigate the possibility of the two clusters to be physically related. We aim to recover the present-day stellar membership in the open clusters Collinder 135 and UBC 7 (300 pc from the Sun), to constrain their kinematic parameters, ages and masses, and to restore their primordial phase space configuration. The most reliable cluster members are selected with our traditional method modified for the use of Gaia DR2 data. Numerical simulations use the integration of cluster trajectories backwards in time with our original high order Hermite4 code \textbackslash PGRAPE. We constrain the age, spatial coordinates and velocities, radii and masses of the clusters. We estimate the actual separation of the cluster centres equal to 24 pc. The orbital integration shows that the clusters were much closer in the past if their current line-of-sight velocities are very similar and the total mass is more than 7 times larger the mass of the determined most reliable members. We conclude that the two clusters Cr 135 and UBC 7 might very well have formed a physial pair, based on the observational evidence as well as numerical simulations. The probability of a chance coincidence is only about \$2\textbackslash\%\$.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SYMMKWIN\\2009.html}}
@article{krause_physics_2020, title = {The {{Physics}} of {{Star Cluster Formation}} and {{Evolution}}}, author = {Krause, Martin G. H. and Offner, Stella S. R. and Charbonnel, Corinne and Gieles, Mark and Klessen, Ralf S. and {Vazquez-Semadeni}, Enrique and {Ballesteros-Paredes}, Javier and Girichidis, Philipp and Kruijssen, J. M. Diederik and Ward, Jacob L. and Zinnecker, Hans}, year = {2020}, month = may, journal = {Space Science Reviews}, volume = {216}, number = {4}, eprint = {2005.00801}, pages = {64}, urldate = {2020-05-05}, abstract = {Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\LLUE5S3K\\2005.html}}
@article{kravtsov_stellar_2022, title = {Stellar Collisions in Globular Clusters: The Origin of Multiple Stellar Populations}, shorttitle = {Stellar Collisions in Globular Clusters}, author = {Kravtsov, Valery and Dib, Sami and Calderon, Francisco A. and Belinchon, Jose A.}, year = {2022}, month = mar, journal = {arXiv:2203.02893 [astro-ph]}, eprint = {2203.02893}, primaryclass = {astro-ph}, urldate = {2022-03-08}, abstract = {Two generations of stars, G1 and G2, typically populate Galactic globular clusters (GCs). The origin of G2 stars is unclear. We uncover two empirical dependencies between GC characteristics, which can be explained by the formation of G2 Main-Sequence (MS) stars due to collision\textbackslash merging of their primordial counterparts (G1). A similar genesis of both G2 stars and peculiar objects like low-mass X-ray binaries and millisecond pulsars is also implied. Indeed, we find a significant (at a confidence level {$>$} 99,9\%) anti-correlation between the fraction of G1 red giants (N\_\{G1\}/N\_\{tot\}) and stellar encounter rates among 51 GCs. Moreover, a Milky Way-like initial mass function (IMF) requires a large fraction of MS stars with masses M\_ms {$<$} 0.5 M\_sun, more specifically at least \textasciitilde 50\% with [0.1-0.5] M\_sun. Unlike cluster mass loss, stellar collisions\textbackslash merging retain these G1 stars by converting them into more massive G2 ones, with mainly M\_ms {$>$} 0.5 M\_sun. This process coupled with a decreasing relative mass loss with increasing GC masses implies a smaller (N\_\{G1\}/N\_\{tot\}) in more massive GCs with a shallower present day MF. From data for 35 GCs, we find that such an anti-correlation is significant at 98.3\% confidence level (Spearman's correlation) for 12 most massive GCs (M\_GC {$>$} 10\^\{5.3\} M\_sun) and it is at a confidence level of 89\textbackslash\% for the 12 least massive GCs (M\_GC {$<$} 10\^\{5.1\} M\_sun). Other fractions of G1 and G2 stars observed at the bottom of the MS as compared with the red giant branch in a few GCs are consistent with the scenario proposed here.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\PRWJPI6P\\2203.html}}
@article{krone-martins_upmask:_2014, title = {{{UPMASK}}: Unsupervised Photometric Membership Assignment in Stellar Clusters}, shorttitle = {{{UPMASK}}}, author = {{Krone-Martins}, A. and Moitinho, A.}, year = {2014}, month = jan, journal = {Astronomy and Astrophysics}, volume = {561}, pages = {A57}, doi = {10.1051/0004-6361/201321143}, urldate = {2019-09-19}, abstract = {{$<$}BR /{$>$} Aims: We develop a method for membership assignment in stellar clusters using only photometry and positions. The method is aimed to be unsupervised, data driven, model free, and to rely on as few assumptions as possible. {$<$}BR /{$>$} Methods: The approach followed in this work for membership assessment is based on an iterative process, principal component analysis, clustering algorithm, and kernel density estimations. The method, UPMASK, is able to take into account arbitrary error models. An implementation in R was tested on simulated clusters that covered a broad range of ages, masses, distances, reddenings, and also on real data of cluster fields. {$<$}BR /{$>$} Results: Running UPMASK on simulations showed that the method effectively separates cluster and field populations. The overall spatial structure and distribution of cluster member stars in the colour-magnitude diagram were recovered under a broad variety of conditions. For a set of 360 simulations, the resulting true positive rates (a measurement of purity) and member recovery rates (a measurement of completeness) at the 90\% membership probability level reached high values for a range of open cluster ages (10\textsuperscript{7.1} - 10\textsuperscript{9.5} yr), initial masses (0.5 - 10 \texttimes{} 10\textsuperscript{3}M\textsubscript{{$\Sun$}}) and heliocentric distances (0.5 - 4.0 kpc). UPMASK was also tested on real data from the fields of open cluster Haffner 16 and of the closely projected clusters Haffner 10 and Czernik 29. These tests showed that even for moderate variable extinction and cluster superposition, the method yielded useful cluster membership probabilities and provided some insight into their stellar contents. The UPMASK implementation will be available at the CRAN archive.}, langid = {english}, keywords = {OC Analysis,Open Source,Open Source OC Analysis Method,Read}, file = {/home/ehunt/Zotero/storage/36UXVSB8/Krone-Martins_Moitinho_2014_UPMASK_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\36UXVSB8\\Krone-Martins_Moitinho_2014_UPMASK.pdf}}
@article{kroupa_variation_2001, title = {On the Variation of the Initial Mass Function}, author = {Kroupa, Pavel}, year = {2001}, month = apr, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {322}, pages = {231--246}, issn = {0035-8711}, doi = {10.1046/j.1365-8711.2001.04022.x}, urldate = {2022-04-04}, abstract = {A universal initial mass function (IMF) is not intuitive, but so far no convincing evidence for a variable IMF exists. The detection of systematic variations of the IMF with star-forming conditions would be the Rosetta Stone for star formation. In this contribution an average or Galactic-field IMF is defined, stressing that there is evidence for a change in the power-law index at only two masses: near 0.5Msolar and near 0.08Msolar. Using this supposed universal IMF, the uncertainty inherent in any observational estimate of the IMF is investigated by studying the scatter introduced by Poisson noise and the dynamical evolution of star clusters. It is found that this apparent scatter reproduces quite well the observed scatter in power-law index determinations, thus defining the fundamental limit within which any true variation becomes undetectable. The absence of evidence for a variable IMF means that any true variation of the IMF in well-studied populations must be smaller than this scatter. Determinations of the power-law indices {$\alpha$} are subject to systematic errors arising mostly from unresolved binaries. The systematic bias is quantified here, with the result that the single-star IMFs for young star clusters are systematically steeper by {$\Delta\alpha\sptilde$}0.5 between 0.1 and 1Msolar than the Galactic-field IMF, which is populated by, on average, about 5-Gyr-old stars. The MFs in globular clusters appear to be, on average, systematically flatter than the Galactic-field IMF (Piotto \& Zoccali; Paresce \& De Marchi), and the recent detection of ancient white-dwarf candidates in the Galactic halo and the absence of associated low-mass stars (Ibata et al.; M\'endez \& Minniti) suggest a radically different IMF for this ancient population. Star formation in higher metallicity environments thus appears to produce relatively more low-mass stars. While still tentative, this is an interesting trend, being consistent with a systematic variation of the IMF as expected from theoretical arguments.}, keywords = {Astrophysics,BINARIES: GENERAL,GLOBULAR CLUSTERS: GENERAL,MASS FUNCTION,OPEN CLUSTERS AND ASSOCIATIONS: GENERAL,STARS: FORMATION,STARS: KINEMATICS,STARS: LUMINOSITY FUNCTION}, annotation = {ADS Bibcode: 2001MNRAS.322..231K}}
@article{kruijssen_phoenix_2020, title = {The {{Phoenix}} Stellar Stream Rose from the Ashes of an Ancient Star Cluster}, author = {Kruijssen, J. M. Diederik}, year = {2020}, month = jul, journal = {Nature}, volume = {583}, number = {7818}, eprint = {2009.12371}, pages = {687--688}, issn = {0028-0836, 1476-4687}, doi = {10.1038/d41586-020-02046-5}, urldate = {2020-10-07}, abstract = {Observations of an ancient stellar stream provide the first evidence of a vanished population of extremely metal-poor stellar clusters. Their remnants might reveal how the early assembly of the Milky Way proceeded.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\XZ5TSYQ8\\2009.html}}
@article{krumholz_how_2020, title = {How Do Bound Star Clusters Form?}, author = {Krumholz, Mark R. and McKee, Christopher F.}, year = {2020}, month = mar, journal = {arXiv:1909.01565 [astro-ph]}, eprint = {1909.01565}, primaryclass = {astro-ph}, urldate = {2020-03-09}, abstract = {Gravitationally-bound clusters that survive gas removal represent an unusual mode of star formation in the Milky Way and similar spiral galaxies. While forming, they can be distinguished observationally from unbound star formation by their high densities, virialised velocity structures, and star formation histories that accelerate toward the present, but extend multiple free-fall times into the past. In this paper we examine several proposed scenarios for how such structures might form and evolve, and carry out a Bayesian analysis to test these models against observed distributions of protostellar age, counts of young stellar objects relative to gas, and the overall star formation rate of the Milky Way. We show that models in which the acceleration of star formation is due either to a large-scale collapse or a time-dependent increase in star formation efficiency are unable to satisfy the combined set of observational constraints. In contrast, models in which clusters form in a "conveyor belt" mode where gas accretion and star formation occur simultaneously, but the star formation rate per free-fall time is low, can match the observations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GURKKQND\\1909.html}}
@article{krumholz_radiationhydrodynamic_simulations_2012, title = {Radiation-Hydrodynamic Simulations of the Formation of Orion-like Star Clusters. {{II}}. {{The}} Initial Mass Function from Winds, Turbulence, and Radiation}, author = {Krumholz, Mark R. and Klein, Richard I. and McKee, Christopher F.}, year = {2012}, month = jul, volume = {754}, number = {1}, eprint = {1203.2620}, primaryclass = {astro-ph.SR}, pages = {71}, doi = {10.1088/0004-637X/754/1/71}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,ISM: clouds,mass function,radiative transfer,stars: formation,stars: luminosity function,turbulence}}
@article{krumholz_star_2019, title = {Star {{Clusters Across Cosmic Time}}}, author = {Krumholz, Mark R. and McKee, Christopher F. and {Bland-Hawthorn}, Joss}, year = {2019}, month = aug, journal = {Annual Review of Astronomy and Astrophysics}, volume = {57}, number = {1}, eprint = {1812.01615}, pages = {227--303}, issn = {0066-4146, 1545-4282}, doi = {10.1146/annurev-astro-091918-104430}, urldate = {2020-09-14}, abstract = {Star clusters stand at the intersection of much of modern astrophysics: the interstellar medium, gravitational dynamics, stellar evolution, and cosmology. Here we review observations and theoretical models for the formation, evolution, and eventual disruption of star clusters. Current literature suggests a picture of this life cycle with several phases: \textbullet{} Clusters form in hierarchically-structured, accreting molecular clouds that convert gas into stars at a low rate per dynamical time until feedback disperses the gas.}, archiveprefix = {arxiv}, langid = {english}, keywords = {\_tablet\_modified,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2IISMCSP\\Krumholz et al_2019_Star Clusters Across Cosmic Time.pdf}}
@article{kuhn_kinematics_2019, title = {Kinematics in {{Young Star Clusters}} and {{Associations}} with {{Gaia DR2}}}, author = {Kuhn, Michael A. and Hillenbrand, Lynne A. and Sills, Alison and Feigelson, Eric D. and Getman, Konstantin V.}, year = {2019}, month = jan, journal = {The Astrophysical Journal}, volume = {870}, pages = {32}, issn = {0004-637X}, doi = {10.3847/1538-4357/aaef8c}, urldate = {2022-03-24}, abstract = {The Gaia mission has opened a new window into the internal kinematics of young star clusters at the sub-km s-1 level, with implications for our understanding of how star clusters form and evolve. We use a sample of 28 clusters and associations with ages from {$\sim$}1-5 Myr, where lists of members are available from previous X-ray, optical, and infrared studies. Proper motions from Gaia DR2 reveal that at least 75\% of these systems are expanding; however, rotation is only detected in one system. Typical expansion velocities are on the order of {$\sim$}0.5 km s-1, and in several systems, there is a positive radial gradient in expansion velocity. Systems that are still embedded in molecular clouds are less likely to be expanding than those that are partially or fully revealed. One-dimensional velocity dispersions, which range from \{{$\sigma$} \}1\{\{D\}\}=1 to 3 km s-1, imply that most of the stellar systems in our sample are supervirial and that some are unbound. In star-forming regions that contain multiple clusters or subclusters, we find no evidence that these groups are coalescing, implying that hierarchical cluster assembly, if it occurs, must happen rapidly during the embedded stage.}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general,stars: formation,stars: kinematics and dynamics}, annotation = {ADS Bibcode: 2019ApJ...870...32K}}
@article{kumaran_active_2018, title = {Active {{Metric Learning}} for {{Supervised Classification}}}, author = {Kumaran, Krishnan and Papageorgiou, Dimitri and Chang, Yutong and Li, Minhan and Tak{\'a}{\v c}, Martin}, year = {2018}, month = mar, journal = {arXiv:1803.10647 [cs, stat]}, eprint = {1803.10647}, primaryclass = {cs, stat}, urldate = {2020-02-05}, abstract = {Clustering and classification critically rely on distance metrics that provide meaningful comparisons between data points. We present mixed-integer optimization approaches to find optimal distance metrics that generalize the Mahalanobis metric extensively studied in the literature. Additionally, we generalize and improve upon leading methods by removing reliance on pre-designated "target neighbors," "triplets," and "similarity pairs." Another salient feature of our method is its ability to enable active learning by recommending precise regions to sample after an optimal metric is computed to improve classification performance. This targeted acquisition can significantly reduce computational burden by ensuring training data completeness, representativeness, and economy. We demonstrate classification and computational performance of the algorithms through several simple and intuitive examples, followed by results on real image and medical datasets.}, archiveprefix = {arxiv}, keywords = {\_tablet,Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{lada_embedded_2003, title = {Embedded {{Clusters}} in {{Molecular Clouds}}}, author = {Lada, Charles J. and Lada, Elizabeth A.}, year = {2003}, journal = {Annual Review of Astronomy and Astrophysics}, volume = {41}, pages = {57}, issn = {0066-4146}, doi = {10.1146/annurev.astro.41.011802.094844}, urldate = {2019-11-18}, abstract = {Stellar clusters are born embedded within giant molecular clouds (GMCs) and during their formation and early evolution are often only visible at infrared wavelengths, being heavily obscured by dust. Over the past 15 years advances in infrared detection capabilities have enabled the first systematic studies of embedded clusters in galactic molecular clouds. In this article we review the current state of empirical knowledge concerning these extremely young protocluster systems. From a survey of the literature we compile the first extensive catalog of galactic embedded clusters. We use the catalog to construct the mass function and estimate the birthrate for embedded clusters within 2 kpc of the sun. We find that the embedded cluster birthrate exceeds that of visible open clusters by an order of magnitude or more indicating a high infant mortality rate for protocluster systems. Less than 4-7\% of embedded clusters survive emergence from molecular clouds to become bound clusters of Pleiades age. The vast majority (90\%) of stars that form in embedded clusters form in rich clusters of 100 or more members with masses in excess of 50 M\textsubscript{{$\Sun$}}. Moreover, observations of nearby cloud complexes indicate that embedded clusters account for a significant (70-90\%) fraction of all stars formed in GMCs. We review the role of embedded clusters in investigating the nature of the initial mass function (IMF) that, in one nearby example, has been measured over the entire range of stellar and substellar mass, from OB stars to substellar objects near the deuterium burning limit. We also review the role embedded clusters play in the investigation of circumstellar disk evolution and the important constraints they provide for understanding the origin of planetary systems. Finally, we discuss current ideas concerning the origin and dynamical evolution of embedded clusters and the implications for the formation of bound open clusters.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JSAVJBCX\\abstract.html}}
@article{lahen_griffin_2020, title = {The {{GRIFFIN}} Project -- {{Formation}} of Star Clusters with Individual Massive Stars in a Simulated Dwarf Galaxy Starburst}, author = {Lah{\'e}n, Natalia and Naab, Thorsten and Johansson, Peter H. and Elmegreen, Bruce and Hu, Chia-Yu and Walch, Stefanie and Steinwandel, Ulrich P. and Moster, Benjamin P.}, year = {2020}, month = feb, journal = {arXiv:1911.05093 [astro-ph]}, eprint = {1911.05093}, primaryclass = {astro-ph}, urldate = {2020-02-19}, abstract = {We describe a population of young star clusters (SCs) formed in a hydrodynamical simulation of a gas-rich dwarf galaxy merger resolved with individual massive stars at sub-parsec spatial resolution. The simulation is part of the GRIFFIN (Galaxy Realizations Including Feedback From INdividual massive stars) project. The star formation environment during the simulation spans seven orders of magnitude in gas surface density and thermal pressure, and the global star formation rate surface density (\$\textbackslash Sigma\_\textbackslash mathrm\{SFR\}\$) varies by more than three orders of magnitude during the simulation. Young SCs more massive than \$M\_\{\textbackslash mathrm\{*,cl\}\}\textbackslash sim 10\^\{2.5\}\textbackslash,M\_\{\textbackslash odot\}\$ form along a mass function with a power-law index \$\textbackslash alpha\textbackslash sim-1.7\$ (\$\textbackslash alpha\textbackslash sim-2\$ for \$M\_\{\textbackslash mathrm\{*,cl\}\}\textbackslash gtrsim10\^\{3\}\textbackslash,M\_\{\textbackslash odot\}\$) at all merger phases, while the normalization and the highest SC masses (up to \$\textbackslash sim 10\^6 M\_\{\textbackslash odot\}\$) correlate with \$\textbackslash Sigma\_\textbackslash mathrm\{SFR\}\$. The cluster formation efficiency varies from \$\textbackslash Gamma\textbackslash sim20\textbackslash\%\$ in early merger phases to \$\textbackslash Gamma\textbackslash sim80\textbackslash\%\$ at the peak of the starburst and is compared to observations and model predictions. The massive SCs (\$\textbackslash gtrsim10\^4\textbackslash,M\_\{\textbackslash odot\}\$) have sizes and mean surface densities similar to observed young massive SCs. Simulated lower mass clusters appear slightly more concentrated than observed. All SCs form on timescales of a few Myr and lose their gas rapidly resulting in typical stellar age spreads between \$\textbackslash sigma\textbackslash sim0.1-2\$ Myr (\$1\textbackslash sigma\$), consistent with observations. The age spreads increase with cluster mass, with the most massive cluster (\$\textbackslash sim10\^6\textbackslash, M\_\{\textbackslash odot\}\$) reaching a spread of \$5\textbackslash, \textbackslash mathrm\{Myr\}\$ once its hierarchical formation finishes. Our study shows that it is now feasible to investigate the SC population of entire galaxies with novel high-resolution numerical simulations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\W3T98FN5\\1911.html}}
@article{latif_formation_2020, title = {Formation of {{Pop II}} Star Clusters in the Aftermath of a Pair Instability Supernova}, author = {Latif, Muhammad A. and Schleicher, Dominik}, year = {2020}, month = oct, journal = {arXiv:2007.13213 [astro-ph]}, eprint = {2007.13213}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {Pop II stars formed a few hundred million years after the Big Bang were key drivers of cosmic reionization and building blocks of high redshift galaxies. How and when these stars formed is a subject of ongoing research. We conduct cosmological radiation hydrodynamical simulations to investigate the formation of Pop II star clusters in dark matter halos forming at \$z=10-25\$ in the aftermath of a pair instability supernova (PISN). Our simulations model the formation of Pop III and Pop II stars in a self-consistent manner along with their radiative, chemical and SN feedback in halos of \$\textbackslash rm 5 \textbackslash times 10\^5- 7 \textbackslash times 10\^7\textasciitilde M\_\{\textbackslash odot\}\$. We find that a PISN evacuates the gas from halos \$\textbackslash rm \textbackslash leq 3 \textbackslash times 10\^\{6\}\textasciitilde M\_\{\textbackslash odot\}\$ and thereafter shuts off in situ star formation for at-least 30 Myr. Pop II stellar clusters of \$\textbackslash rm 923\textasciitilde M\_\{\textbackslash odot\}\$ and \$\textbackslash rm 6800\textasciitilde M\_\{\textbackslash odot\}\$ form in halos of \$\textbackslash rm 3.5 \textbackslash times 10\^7\textasciitilde M\_\{\textbackslash odot\}\$ and \$\textbackslash rm 7.2 \textbackslash times 10\^7\textasciitilde M\_\{\textbackslash odot\}\$, respectively. The mode of star formation is highly episodic and mainly regulated by Pop II SN feedback. The average star formation rates are \$\textbackslash rm 10\^\{-5\}-10\^\{-4\}\textasciitilde M\_\{\textbackslash odot\}/yr\$ and the star formation efficiency is less than 1\textbackslash\%.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6EUR6JG4\\2007.html}}
@article{leiner_census_blue_2021, title = {A Census of Blue Stragglers in Gaia {{DR2}} Open Clusters as a Test of Population Synthesis and Mass Transfer Physics}, author = {Leiner, Emily M. and Geller, Aaron}, year = {2021}, month = feb, volume = {908}, number = {2}, eprint = {2101.11047}, primaryclass = {astro-ph.SR}, pages = {229}, doi = {10.3847/1538-4357/abd7e9}, archiveprefix = {arxiv}, keywords = {1160,154,168,2153,2155,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Binary stars,Blue straggler stars,Multiple star evolution,Open star clusters,Roche lobe overflow}}
@article{leitinger_widefield_view_2023, title = {A {{Wide-Field View}} on {{Multiple Stellar Populations}} in 28 {{Milky Way Globular Clusters}}}, author = {Leitinger, E. and Baumgardt, H. and {Cabrera-Ziri}, I. and Hilker, M. and Pancino, E.}, year = {2023}, month = jan, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {520}, number = {1}, eprint = {2301.04166}, primaryclass = {astro-ph}, pages = {1456--1480}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stad093}, urldate = {2023-04-10}, abstract = {The majority of Galactic globular clusters (GCs) contain multiple stellar populations displaying specific chemical abundance variations. In particular, GCs generally contain a `primordial' population with abundances similar to field stars, along with an `enriched' population exhibiting light element anomalies. In this paper we present a homogeneous and wide-view analysis of multiple stellar populations in 28 Galactic GCs. By using a combination of HST photometry together with wide-field, ground-based photometry we are able to analyse between 84\% and 99\% of all stars in each cluster. For each GC, we classify stars into separate sub-populations using the well-established \$C\_\{\textbackslash rm\{UBI\}\}\$ colour index, and investigate the spatial distributions of these populations. Our results show that dynamically young GCs can contain either centrally concentrated enriched or primordial populations, or no centrally concentrated population. Dynamically old GCs show fully mixed populations as expected. The existence of clusters born with centrally concentrated primordial (and homogeneously mixed) populations exacerbates the mass-budget problem facing many cluster formation scenarios. The diversity in these results also highlights the need for additional theories that can account for the wide variety of initial conditions that we find. We finally investigate the enriched star fraction as a function of different global parameters in our GC sample, using also data for young and low-mass clusters from the Small- and Large Magellanic Clouds and confirm earlier results that the enriched star fraction strongly correlates with the initial mass of a cluster.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{leung_deep_2019, title = {Deep Learning of Multi-Element Abundances from High-Resolution Spectroscopic Data}, author = {Leung, Henry W. and Bovy, Jo}, year = {2019}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {483}, pages = {3255--3277}, issn = {0035-8711}, doi = {10.1093/mnras/sty3217}, urldate = {2022-12-19}, abstract = {Deep learning with artificial neural networks is increasingly gaining attention because of its potential for data-driven astronomy. However, this methodology usually does not provide uncertainties and does not deal with incompleteness and noise in the training data. In this work, we design a neural network for high-resolution spectroscopic analysis using APO Galactic Evolution Experiment (APOGEE) data that mimics the methodology of standard spectroscopic analyses: stellar parameters are determined using the full wavelength range, but individual element abundances use censored portions of the spectrum. We train this network with a customized objective function that deals with incomplete and noisy training data and apply dropout variational inference to derive uncertainties on our predictions. We determine parameters and abundances for 18 individual elements at the \{{$\approx$} \} 0.03 dex level, even at low signal-to-noise ratio. We demonstrate that the uncertainties returned by our method are a realistic estimate of the precision and they automatically blow up when inputs or outputs outside of the training set are encountered, thus shielding users from unwanted extrapolation. By using standard deep-learning tools for GPU acceleration, our method is extremely fast, allowing analysis of the entire APOGEE data set of {$\approx$}250 000 spectra in 10 min on a single, low-cost GPU. We release the stellar parameters and 18 individual-element abundances with associated uncertainty for the entire APOGEE DR14 data set. Simultaneously, we release astroNN, a well-tested, open-source PYTHON package developed for this work, but that is also designed to be a general package for deep learning in astronomy. astroNN is available at https://github.com/henrysky/astroNN with extensive documentation at http://astroNN.readthedocs.io.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,methods: data analysis,stars: abundances,stars: fundamental parameters,techniques: spectroscopic}, annotation = {ADS Bibcode: 2019MNRAS.483.3255L}}
@article{li_lisc_2022, title = {{{LISC Catalog}} of {{Star Clusters}}. {{I}}. {{Galactic Disk Clusters}} in {{Gaia EDR3}}}, author = {Li, Zhongmu and Deng, Yangyang and Chi, Huanbin and Chen, Jing and Liu, Xuejie and Yan, Chen and Chen, Wen and Guo, Wenkai and Xia, Tao}, year = {2022}, month = feb, journal = {The Astrophysical Journal Supplement Series}, volume = {259}, number = {1}, pages = {19}, publisher = {{The American Astronomical Society}}, issn = {0067-0049}, doi = {10.3847/1538-4365/ac3c49}, urldate = {2023-02-14}, abstract = {This work searches for the candidates of Galactic disk star clusters in Gaia Early Data Release 3 (Gaia EDR3) and determines their basic parameters from color\textendash magnitude diagrams (CMDs). A friends-of-friends method for membership determination and stellar population models including binary stars (ASPS) and rotating stars are adopted. As a result, 868 new star cluster candidates are found, besides 2729 known ones. When checking the CMD of each candidate, 61 new candidates show main sequences including a turnoff, which suggests that they are real star clusters. The basic parameters, including distance modulus, color excess, metallicity, age (or age range), primordial binary fraction, and rotating star fraction, are determined carefully by fitting the morphologies of CMDs of 61 newly identified star clusters and 594 known star clusters, which have relatively clear main sequences. The CMDs are fitted in considerable detail to ensure the reliability of property parameters of clusters. All final results are included in a new star cluster catalog, which is named LI team's Star Cluster (LISC), and the catalog is available in the Zenodo repository.}, langid = {english}}
@article{li_lisc_2023, title = {{{LISC Catalog}} of {{Star Clusters}}. {{II}}. {{High Galactic Latitude Open Clusters}} in {{Gaia EDR3}}}, author = {Li, Zhongmu and Mao, Caiyan}, year = {2023}, month = feb, journal = {The Astrophysical Journal Supplement Series}, volume = {265}, number = {1}, pages = {3}, publisher = {{The American Astronomical Society}}, issn = {0067-0049}, doi = {10.3847/1538-4365/acaf7d}, urldate = {2023-02-14}, abstract = {It is well known that there are few open clusters (OCs) in the high-latitude region of the Milky Way galaxy, because most star formation takes place in the thin disk. It is therefore crucial to look for high Galactic latitude OCs, in order to understand OCs and the Galactic parts outside the plane well. This work looks for high Galactic latitude OCs in Gaia Early Data Release 3, and determines their basic parameters from color\textendash magnitude diagrams (CMDs) if the main sequence is included in CMDs. The friend-of-friend method is applied to the determination of the membership of stars. Star groups with more than 20 bright (G {$<$} 18 mag) stars are taken as OC candidates, and these candidates are finally verified by the observed CMDs including stars fainter than 18 mag in the G band. After crossmatching with previous catalogs, 56 new OC candidates are found in the high Galactic latitude region with {$\mid$}b{$\mid$} {$\geq$} 25\textdegree, in which 35 have somewhat clear CMDs and are suggested as newly discovered OCs. Finally, eight of the new OCs are confirmed again by the pyUPMASK technique. The new sample increases the total number of known high Galactic latitude OC candidates significantly. The distance modulus, color excess, metallicity, age, and binary fraction of 35 newly discovered OCs are determined by fitting their observed CMDs to the ASPS stellar population models. All the results are included in the new star cluster catalog, LISC, as its second part (LISC II).}, langid = {english}}
@article{li_modelling_2020, title = {Modelling Unresolved Binaries of Open Clusters in Color-Magnitude Diagram. {{I}}. Method and Application of {{NGC3532}}}, author = {Li, Lu and Shao, Zhengyi and Li, Zhao-Zhou and Yu, Jincheng and Zhong, Jing and Chen, Li}, year = {2020}, month = aug, journal = {arXiv:2008.04684 [astro-ph]}, eprint = {2008.04684}, primaryclass = {astro-ph}, urldate = {2020-08-12}, abstract = {The binary properties of open clusters place crucial constraints on star formation theory and clusters' dynamical evolution. We develop a comprehensive approach that models the color-magnitude diagram (CMD) of the cluster members as the mixture of single stars and photometric unresolved binaries. This method enables us to infer the binary properties, including the binary fraction \$f\_\textbackslash mathrm\{b\}\$ and binary mass-ratio distribution index \$\textbackslash gamma\_q\$ when a power-law is assumed, with high accuracy and precision, which were unfeasible in conventional methods. We employ a modified Gaussian process to determine the main sequence ridge line and its scatter from the observed CMD as model input. As a first example, we apply the method to the open cluster NGC3532 with the Gaia DR2 photometry. For the cluster members within a magnitude range corresponding to FGK dwarfs, we obtain \$f\_\textbackslash mathrm\{b\} = 0.267\textbackslash pm0.019\$ and \$\textbackslash gamma\_q = - 0.10\textbackslash pm0.22\$ for binaries with mass ratio \$q {$>$} 0.2\$. The \$f\_\textbackslash mathrm\{b\}\$ value is consistent with the previous work on NGC3532 and smaller than that of field stars. The close to zero \$\textbackslash gamma\_q\$ indicates that the mass ratios of binaries follow a nearly uniform distribution. For the first time, we unveil that the stars with smaller mass or in the inner region tend to have lower \$f\_\textbackslash mathrm\{b\}\$ and more positive value of \$\textbackslash gamma\_q\$ due to the lack of low mass-ratio binaries. The clear dependences of binary properties on mass and radius are most likely caused by the internal dynamics.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\P84EQFSU\\2008.html}}
@article{lim_star_2020, title = {Star {{Cluster Formation}} in {{Orion A}}}, author = {Lim, Wanggi and Nakamura, Fumitaka and Wu, Benjamin and Bisbas, Thomas G. and Tan, Jonathan C. and Chambers, Edward and Bally, John and Kong, Shuo and McGehee, Peregrine and Lis, Dariusz C. and {Ossenkopf-Okada}, Volker and {S{\'a}nchez-Monge}, {\'A}lvaro}, year = {2020}, month = apr, journal = {arXiv:2004.03668 [astro-ph]}, eprint = {2004.03668}, primaryclass = {astro-ph}, urldate = {2020-04-14}, abstract = {We introduce new analysis methods for studying the star cluster formation processes in Orion A, especially examining the scenario of a cloud-cloud collision. We utilize the CARMA-NRO Orion survey \$\^\{13\}\$CO (1-0) data to compare molecular gas to the properties of YSOs from the SDSS III IN-SYNC survey. We show that the increase of \$v\_\{\textbackslash rm 13CO\} - v\_\{\textbackslash rm YSO\}\$ and \$\textbackslash Sigma\$ scatter o older YSOs can be signals of cloud-cloud collision. SOFIA-upGREAT 158\$\textbackslash mu\$m [CII] archival data toward the northern part of Orion A are also compared to the \$\^\{13\}\$CO data to test whether the position and velocity offsets between the emission from these two transitions resemble those predicted by a cloud-cloud collision model. We find that the northern part of Orion A, including regions ONC-OMC-1, OMC-2, OMC-3 and OMC-4, shows qualitative agreements with the cloud-cloud collision scenario, while in one of the southern regions, NGC1999, there is no indication of such a process in causing the birth of new stars. On the other hand, another southern cluster, L1641N, shows slight tendencies of cloud-cloud collision. Overall, our results support the cloud-cloud collision process as being an important mechanism for star cluster formation in Orion A.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CYTQFTAF\\2004.html}}
@article{lin_detection_2021, title = {Detection of Gravitational Waves Using {{Bayesian}} Neural Networks}, author = {Lin, Yu-Chiung and Wu, Jiun-Huei Proty}, year = {2021}, month = mar, journal = {Physical Review D}, volume = {103}, pages = {063034}, issn = {1550-79980556-2821}, doi = {10.1103/PhysRevD.103.063034}, urldate = {2022-12-19}, abstract = {We propose a new model of Bayesian neural networks to not only detect the events of compact binary coalescence in the observational data of gravitational waves (GW) but also identify the full length of the event duration including the inspiral stage. This is achieved by incorporating the Bayesian approach into the convolutional, long short-term memory, fully connected deep neural network classifier, which integrates together the convolutional neural network (CNN) and the long short-term memory recurrent neural network (LSTM). Our model successfully detect all seven binary black hole events in the LIGO Livingston O2 data, with the periods of their GW waveforms correctly labeled. The ability of a Bayesian approach for uncertainty estimation enables a newly defined `awareness' state for recognizing the possible presence of signals of unknown types, which is otherwise rejected in a non-Bayesian model. Such data chunks labeled with the awareness state can then be further investigated rather than overlooked. Performance tests with 40,960 training samples against 512 chunks of 8-second real noise mixed with mock signals of various optimal signal-to-noise ratio 0 {$\leq\rho$}opt{$\leq$}18 show that our model recognizes 90\% of the events when {$\rho$}opt{$>$}7 (100\% when {$\rho$}opt{$>$}8.5 ) and successfully labels more than 95\% of the waveform periods when {$\rho$}opt{$>$}8 . The latency between the arrival of peak signal and generating an alert with the associated waveform period labeled is only about 20 seconds for an unoptimized code on a moderate GPU-equipped personal computer. This makes our model possible for nearly real-time detection and for forecasting the coalescence events when assisted with deeper training on a larger dataset using the state-of-art HPCs.}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Instrumentation and Methods for Astrophysics,Computer Science - Machine Learning,Physics - Data Analysis,Statistics - Machine Learning,Statistics and Probability}, annotation = {ADS Bibcode: 2021PhRvD.103f3034L}}
@article{lindegren_gaia_2018, title = {Gaia {{Data Release}} 2. {{The}} Astrometric Solution}, author = {Lindegren, L. and Hern{\'a}ndez, J. and Bombrun, A. and Klioner, S. and Bastian, U. and {Ramos-Lerate}, M. and {de Torres}, A. and Steidelm{\"u}ller, H. and Stephenson, C. and Hobbs, D. and Lammers, U. and Biermann, M. and Geyer, R. and Hilger, T. and Michalik, D. and Stampa, U. and McMillan, P. J. and Casta{\~n}eda, J. and Clotet, M. and Comoretto, G. and Davidson, M. and Fabricius, C. and Gracia, G. and Hambly, N. C. and Hutton, A. and Mora, A. and Portell, J. and {van Leeuwen}, F. and Abbas, U. and Abreu, A. and Altmann, M. and Andrei, A. and Anglada, E. and {Balaguer-N{\'u}{\~n}ez}, L. and Barache, C. and Becciani, U. and Bertone, S. and Bianchi, L. and Bouquillon, S. and Bourda, G. and Br{\"u}semeister, T. and Bucciarelli, B. and Busonero, D. and Buzzi, R. and Cancelliere, R. and Carlucci, T. and Charlot, P. and Cheek, N. and Crosta, M. and Crowley, C. and {de Bruijne}, J. and {de Felice}, F. and Drimmel, R. and Esquej, P. and Fienga, A. and Fraile, E. and Gai, M. and Garralda, N. and {Gonz{\'a}lez-Vidal}, J. J. and Guerra, R. and Hauser, M. and Hofmann, W. and Holl, B. and Jordan, S. and Lattanzi, M. G. and Lenhardt, H. and Liao, S. and Licata, E. and Lister, T. and L{\"o}ffler, W. and Marchant, J. and {Martin-Fleitas}, J.-M. and Messineo, R. and Mignard, F. and Morbidelli, R. and Poggio, E. and Riva, A. and Rowell, N. and Salguero, E. and Sarasso, M. and Sciacca, E. and Siddiqui, H. and Smart, R. L. and Spagna, A. and Steele, I. and Taris, F. and Torra, J. and {van Elteren}, A. and {van Reeven}, W. and Vecchiato, A.}, year = {2018}, month = aug, journal = {Astronomy and Astrophysics}, volume = {616}, pages = {A2}, issn = {0004-6361}, doi = {10.1051/0004-6361/201832727}, urldate = {2020-06-24}, abstract = {Context. Gaia Data Release 2 (Gaia DR2) contains results for 1693 million sources in the magnitude range 3 to 21 based on observations collected by the European Space Agency Gaia satellite during the first 22 months of its operational phase. Aims: We describe the input data, models, and processing used for the astrometric content of Gaia DR2, and the validation of these resultsperformed within the astrometry task. Methods: Some 320 billion centroid positions from the pre-processed astrometric CCD observations were used to estimate the five astrometric parameters (positions, parallaxes, and proper motions) for 1332 million sources, and approximate positions at the reference epoch J2015.5 for an additional 361 million mostly faint sources. These data were calculated in two steps. First, the satellite attitude and the astrometric calibration parameters of the CCDs were obtained in an astrometric global iterative solution for 16 million selected sources, using about 1\% of the input data. This primary solution was tied to the extragalactic International Celestial Reference System (ICRS) by means of quasars. The resulting attitude and calibration were then used to calculate the astrometric parameters of all the sources. Special validation solutions were used to characterise the random and systematic errors in parallax and proper motion. Results: For the sources with five-parameter astrometric solutions, the median uncertainty in parallax and position at the reference epoch J2015.5 is about 0.04 mas for bright (G {$<$} 14 mag) sources, 0.1 mas at G = 17 mag, and 0.7 masat G = 20 mag. In the proper motion components the corresponding uncertainties are 0.05, 0.2, and 1.2 mas yr-1, respectively.The optical reference frame defined by Gaia DR2 is aligned with ICRS and is non-rotating with respect to the quasars to within 0.15 mas yr-1. From the quasars and validation solutions we estimate that systematics in the parallaxes depending on position, magnitude, and colour are generally below 0.1 mas, but the parallaxes are on the whole too small by about 0.03 mas. Significant spatial correlations of up to 0.04 mas in parallax and 0.07 mas yr-1 in proper motion are seen on small ({$<$} 1 deg) and intermediate (20 deg) angular scales. Important statistics and information for the users of the Gaia DR2 astrometry are given in the appendices.}, keywords = {astrometry,methods: data analysis,parallaxes,proper motions,reference systems,space vehicles: instruments}}
@article{lindegren_gaia_2021, title = {Gaia {{Early Data Release}} 3 {{The}} Astrometric Solution}, shorttitle = {Gaia {{Early Data Release}} 3}, author = {Lindegren, L. and Klioner, S. A. and Hern{\'a}ndez, J. and Bombrun, A. and {Ramos-Lerate}, M. and Steidelm{\"u}ller, H. and Bastian, U. and Biermann, M. and {de Torres}, A. and Gerlach, E. and Geyer, R. and Hilger, T. and Hobbs, D. and Lammers, U. and McMillan, P. J. and Stephenson, C. A. and Casta{\~n}eda, J. and Davidson, M. and Fabricius, C. and {Gracia-Abril}, G. and Portell, J. and Rowell, N. and Teyssier, D. and Torra, F. and Bartolom{\'e}, S. and Clotet, M. and Garralda, N. and {Gonz{\'a}lez-Vidal}, J. J. and Torra, J. and Abbas, U. and Altmann, M. and Varela, E. Anglada and {Balaguer-N{\'u}{\~n}ez}, L. and Balog, Z. and Barache, C. and Becciani, U. and Bernet, M. and Bertone, S. and Bianchi, L. and Bouquillon, S. and Brown, A. G. A. and Bucciarelli, B. and Busonero, D. and Butkevich, A. G. and Buzzi, R. and Cancelliere, R. and Carlucci, T. and Charlot, P. and Cioni, M.-R. L. and Crosta, M. and Crowley, C. and {del Peloso}, E. F. and {del Pozo}, E. and Drimmel, R. and Esquej, P. and Fienga, A. and Fraile, E. and Gai, M. and {Garcia-Reinaldos}, M. and Guerra, R. and Hambly, N. C. and Hauser, M. and Jan{\ss}en, K. and Jordan, S. and {Kostrzewa-Rutkowska}, Z. and Lattanzi, M. G. and Liao, S. and Licata, E. and Lister, T. A. and L{\"o}ffler, W. and Marchant, J. M. and Masip, A. and Mignard, F. and Mints, A. and Molina, D. and Mora, A. and Morbidelli, R. and Murphy, C. P. and Pagani, C. and Panuzzo, P. and Esteller, X. Pe{\~n}alosa and Poggio, E. and Fiorentin, P. Re and Riva, A. and Sell{\'e}s, A. Sagrist{\`a} and Gimenez, V. Sanchez and Sarasso, M. and Sciacca, E. and Siddiqui, H. I. and Smart, R. L. and Souami, D. and Spagna, A. and Steele, I. A. and Taris, F. and Utrilla, E. and {van Reeven}, W. and Vecchiato, A.}, year = {2021}, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2012.03380}, pages = {A2}, urldate = {2021-01-07}, abstract = {Gaia Early Data Release 3 (Gaia EDR3) contains results for 1.812 billion sources in the magnitude range G = 3 to 21 based on observations collected by the European Space Agency Gaia satellite during the first 34 months of its operational phase. We describe the input data, the models, and the processing used for the astrometric content of Gaia EDR3, as well as the validation of these results performed within the astrometry task. The processing broadly followed the same procedures as for Gaia DR2, but with significant improvements to the modelling of observations. For the first time in the Gaia data processing, colour-dependent calibrations of the line- and point-spread functions have been used for sources with well-determined colours from DR2. In the astrometric processing these sources obtained five-parameter solutions, whereas other sources were processed using a special calibration that allowed a pseudocolour to be estimated as the sixth astrometric parameter. Compared with DR2, the astrometric calibration models have been extended, and the spin-related distortion model includes a self-consistent determination of basic-angle variations, improving the global parallax zero point. Gaia EDR3 gives full astrometric data (positions at epoch J2016.0, parallaxes, and proper motions) for 1.468 billion sources (585 million with five-parameter solutions, 882 million with six parameters), and mean positions at J2016.0 for an additional 344 million. Solutions with five parameters are generally more accurate than six-parameter solutions, and are available for 93\% of the sources brighter than G = 17 mag. The median uncertainty in parallax and annual proper motion is 0.02-0.03 mas at magnitude G = 9 to 14, and around 0.5 mas at G = 20. Extensive characterisation of the statistical properties of the solutions is provided, including the estimated angular power spectrum of parallax bias from the quasars.}, archiveprefix = {arxiv}, keywords = {\_tablet\_modified,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YP4CX6UP\\2012.html}}
@article{lindegren_gaia_2021-1, title = {Gaia {{Early Data Release}} 3: {{Parallax}} Bias versus Magnitude, Colour, and Position}, shorttitle = {Gaia {{Early Data Release}} 3}, author = {Lindegren, L. and Bastian, U. and Biermann, M. and Bombrun, A. and {de Torres}, A. and Gerlach, E. and Geyer, R. and Hern{\'a}ndez, J. and Hilger, T. and Hobbs, D. and Klioner, S. A. and Lammers, U. and McMillan, P. J. and {Ramos-Lerate}, M. and Steidelm{\"u}ller, H. and Stephenson, C. A. and {van Leeuwen}, F.}, year = {2021}, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2012.01742}, pages = {A4}, urldate = {2021-01-04}, abstract = {Gaia Early Data Release 3 (Gaia EDR3) gives trigonometric parallaxes for nearly 1.5 billion sources. Inspection of the EDR3 data for sources identified as quasars reveals that their parallaxes are biased, that is systematically offset from the expected distribution around zero, by a few tens of microarcsec. We attempt to map the main dependencies of the parallax bias in EDR3. In principle this could provide a recipe for correcting the EDR3 parallaxes. For faint sources the quasars provide the most direct way to estimate parallax bias. In order to extend this to brighter sources and a broader range of colours, we use differential methods based on physical pairs (binaries) and sources in the Large Magellanic Cloud. The functional forms of the dependencies are explored by mapping the systematic differences between EDR3 and DR2 parallaxes. The parallax bias is found to depend in a non-trivial way on (at least) the magnitude, colour, and ecliptic latitude of the source. Different dependencies apply to the five- and six-parameter solutions in EDR3. While it is not possible to derive a definitive recipe for the parallax correction, we give tentative expressions to be used at the researcher's discretion and point out some possible paths towards future improvements.}, archiveprefix = {arxiv}, keywords = {\_tablet,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\VRNF296X\\2012.html}}
@article{liu_catalog_2019, title = {A Catalog of Newly Identified Star Clusters in {{GAIA DR2}}}, author = {Liu, Lei and Pang, Xiaoying}, year = {2019}, month = oct, journal = {The Astrophysical Journal Supplement Series}, volume = {245}, number = {2}, eprint = {1910.12600}, pages = {32}, urldate = {2019-10-30}, abstract = {We present the Star cluster Hunting Pipeline (SHiP) which can identify star clusters in GAIA DR2 data, and establish a star cluster catalog for the Galactic disk. A Friend of Friend based cluster finder method is used to identify star clusters using 5-dimensional stellar parameters, \$l, b, \textbackslash varpi, \textbackslash mu\_\textbackslash alpha\textbackslash cos\textbackslash delta\$, and \$\textbackslash mu\_\textbackslash delta\$. Our new catalog contains 2443 star cluster candidates identified from disk stars located within \$|b|=25\^\textbackslash circ\$ and with \$G{$<$}18\$ mag. An automatic isochrone fitting scheme is applied to all cluster candidates. With a combination of parameters obtained from isochrone fitting, we classify cluster candidates into three classes (Class 1, 2 and 3). Class 1 clusters are the most probable star cluster candidates with the most stringent criteria. Most of these clusters are nearby (within 4 kpc). Our catalog is cross-matched with three Galactic star cluster catalogs, Kharchenko et al. (2013), Cantat-Gaudin et al. (2018, 2019), and Bica et al. (2019). The proper motion and parallax of matched star clusters are in good agreement with these earlier catalogs. We discover 76 new star cluster candidates that are not listed in these 3 catalogs. The majority of these are clusters older than log(age/yr)=8.0, and are located in the inner disk with \$|b|{$<$}5\^\textbackslash circ\$. The recent discovery of new star clusters suggests that current Galactic star cluster catalogs are still incomplete. Among the Class 1 cluster candidates, we find 56 candidates for star cluster groups. The pipeline, the catalog and the member list containing all candidates star clusters and star cluster groups have been made publicly available.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,OC Analysis,OC Finder,Read}}
@article{lodieu_3d_view_2019, title = {A {{3D}} View of the {{Hyades}} Stellar and Sub-Stellar Population}, author = {Lodieu, N. and Smart, R. L. and {P{\'e}rez-Garrido}, A. and Silvotti, R.}, year = {2019}, month = mar, volume = {623}, eprint = {1901.07534}, primaryclass = {astro-ph.SR}, pages = {A35}, doi = {10.1051/0004-6361/201834045}, archiveprefix = {arxiv}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,brown dwarfs,open clusters and associations: individual: Hyades,stars: low-mass,surveys}}
@article{logan_unsupervised_2020, title = {Unsupervised Star, Galaxy, {{QSO}} Classification: {{Application}} of {{HDBSCAN}}}, shorttitle = {Unsupervised Star, Galaxy, {{QSO}} Classification}, author = {Logan, C. H. A. and Fotopoulou, S.}, year = {2020}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {633}, pages = {A154}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201936648}, urldate = {2022-04-01}, abstract = {Context. Classification will be an important first step for upcoming surveys aimed at detecting billions of new sources, such as LSST and Euclid, as well as DESI, 4MOST, and MOONS. The application of traditional methods of model fitting and colour-colour selections will face significant computational constraints, while machine-learning methods offer a viable approach to tackle datasets of that volume.}, langid = {english}}
@article{loktin_rotation_2020, title = {Rotation of Open Clusters Based on {{Gaia}} Data. {{Praesepe}}}, author = {Loktin, Alexander V. and Popov, Alexander A.}, year = {2020}, journal = {Astronomische Nachrichten}, volume = {341}, number = {6-7}, pages = {638--644}, issn = {1521-3994}, doi = {10.1002/asna.202013687}, urldate = {2023-02-28}, abstract = {High\textendash precision trigonometric parallaxes, proper motions, and radial velocities of the Gaia DR2 catalog allow us to investigate the problem of open clusters rotation. Such a study could naturally be started with the clusters closest to the Sun, so we chose Praesepe as an object of our study. We selected 908 probable cluster members up to the apparent magnitude G = 19 mag based on their trigonometric parallaxes and proper motions, within 10\textdegree{} distance from the cluster center. We estimated the cluster distance modulus to be 6.36 mag and 6.02 mag using the trigonometric parallaxes of the probable cluster members and by fitting the theoretical isochrone to the cluster hertzsprung-russell (HR) diagram, respectively. The cluster rotation velocity was estimated to be 0.4 km s-1 at the periphery of the cluster, using three different methods. In the future, we will continue the study of clusters rotation, with several nearby open clusters.}, langid = {english}, keywords = {Astronomical databases: miscellaneous \textendash{} celestial mechanics,stellar dynamics \textendash{} Galaxy: Open clusters and associations: individual (Praesepe) \textendash{} methods: data analysis}}
@article{lopez-corredoira_disk_stars_2018, title = {Disk Stars in the {{Milky Way}} Detected beyond 25 Kpc from Its Center}, author = {{L{\'o}pez-Corredoira}, M. and Allende Prieto, C. and Garz{\'o}n, F. and Wang, H. and Liu, C. and Deng, L.}, year = {2018}, month = apr, journal = {Astronomy and Astrophysics}, volume = {612}, pages = {L8}, issn = {0004-6361}, doi = {10.1051/0004-6361/201832880}, urldate = {2023-04-06}, abstract = {Context. The maximum size of the Galactic stellar disk is not yet known. Some studies have suggested an abrupt drop-off of the stellar density of the disk at Galactocentric distances R {$\greaterequivlnt$} 15 kpc, which means that in practice no disk stars or only very few of them should be found beyond this limit. However, stars in the Milky Way plane are detected at larger distances. In addition to the halo component, star counts have placed the end of the disk beyond 20 kpc, although this has not been spectroscopically confirmed so far. Aims: Here, we aim to spectroscopically confirm the presence of the disk stars up to much larger distances. Methods: With data from the LAMOST and SDSS-APOGEE spectroscopic surveys, we statistically derived the maximum distance at which the metallicity distribution of stars in the Galactic plane is distinct from that of the halo populations. Results: Our analysis reveals the presence of disk stars at R {$>$} 26 kpc (99.7\% C.L.) and even at R {$>$} 31 kpc (95.4\% C.L.).}, keywords = {Astrophysics - Astrophysics of Galaxies,Galaxy: structure - Galaxy: disk - Galaxy: abundances}, annotation = {ADS Bibcode: 2018A\&A...612L...8L}}
@article{lu_stellar_2013, title = {{{STELLAR POPULATIONS IN THE CENTRAL}} 0.5 Pc {{OF THE GALAXY}}. {{II}}. {{THE INITIAL MASS FUNCTION}}}, author = {Lu, J. R. and Do, T. and Ghez, A. M. and Morris, M. R. and Yelda, S. and Matthews, K.}, year = {2013}, month = feb, journal = {The Astrophysical Journal}, volume = {764}, number = {2}, pages = {155}, publisher = {{American Astronomical Society}}, issn = {0004-637X}, doi = {10.1088/0004-637X/764/2/155}, urldate = {2022-04-20}, abstract = {The supermassive black hole at the center of the Milky Way plays host to a massive, young cluster that may have formed in one of the most inhospitable environments in the Galaxy. We present new measurements of the global properties of this cluster, including the initial mass function (IMF), age, and cluster mass. These results are based on Keck laser-guide-star adaptive optics observations used to identify the young stars and measure their Kp-band luminosity function as presented in Do et al. A Bayesian inference methodology is developed to simultaneously fit the global properties of the cluster utilizing the observations and extensive simulations of synthetic star clusters. We find that the slope of the mass function for this cluster is {$\alpha$} = 1.7 {$\pm$} 0.2, which is steeper than previously reported, but still flatter than the traditional Salpeter slope of 2.35. The age of the cluster is between 2.5 and 5.8 Myr with 95\% confidence, which is a younger age than typically adopted but consistent within the uncertainties of past measurements. The exact age of the cluster is difficult to determine since our results show two distinct age solutions (3.9 Myr and 2.8 Myr) due to model degeneracies in the relative number of Wolf\textendash Rayet and OB stars. The total cluster mass is between 14,000 and 37,000 M{$\Sun$} above 1 M{$\Sun$} and it is necessary to include multiple star systems in order to fit the observed luminosity function and the number of observed Wolf\textendash Rayet stars. The new IMF slope measurement is now consistent with X-ray observations indicating a factor of 10 fewer X-ray emitting pre-main-sequence stars than expected when compared with a Salpeter IMF. The young cluster at the Galactic center is one of the few definitive examples of an IMF that deviates significantly from the near-universal IMFs found in the solar neighborhood.}, langid = {english}}
@misc{lucchini_moving_2022, title = {Moving {{Groups Across Galactocentric Radius}} with {{Gaia DR3}}}, author = {Lucchini, Scott and Pellett, Emil and D'Onghia, Elena and Aguerri, J. Alfonso L.}, year = {2022}, month = jun, number = {arXiv:2206.10633}, eprint = {2206.10633}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2206.10633}, urldate = {2022-06-27}, abstract = {The kinematic plane of stars near the Sun has proven an indispensable tool for untangling the complexities of the structure of our Milky Way (MW). With ever improving data, numerous kinematic "moving groups" of stars have been better characterized and new ones continue to be discovered. Here we present an improved method for detecting these groups using MGwave, a new open-source 2D wavelet transformation code that we have developed. Our code implements similar techniques to previous wavelet software; however, we include a more robust significance methodology and also allow for the investigation of underdensities which can eventually provide further information about the MW's non-axisymmetric features. Applying MGwave to the latest data release from Gaia (DR3), we detect 45 groups of stars with coherent velocities. We reproduce the majority of the previously detected moving groups in addition to identifying four additional significant candidates: one near Antoja12-GCSIII-13, one near GMG 5, and two with very low \$V\_r\$ and similar \$V\_\textbackslash phi\$ to Hercules. Finally, we have followed these associations of stars beyond the solar neighborhood, from Galactocentric radius of 6.5 to 10\textasciitilde kpc. Most detected groups are extended throughout radius indicating that they are streams of stars possibly due to non-axisymmetric features of the MW.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{luri_gaia_2018, title = {Gaia {{Data Release}} 2 - {{Using Gaia}} Parallaxes}, author = {Luri, X. and Brown, A. G. A. and Sarro, L. M. and Arenou, F. and {Bailer-Jones}, C. a. L. and {Castro-Ginard}, A. and de Bruijne, J. and Prusti, T. and Babusiaux, C. and Delgado, H. E.}, year = {2018}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {616}, pages = {A9}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201832964}, urldate = {2019-09-03}, abstract = {\emph{Context.{$<$}i/{$>$} The second \emph{Gaia{$<$}i/{$>$} data release (\emph{Gaia{$<$}i/{$>$} DR2) provides precise five-parameter astrometric data (positions, proper motions, and parallaxes) for an unprecedented number of sources (more than 1.3 billion, mostly stars). This new wealth of data will enable the undertaking of statistical analysis of many astrophysical problems that were previously infeasible for lack of reliable astrometry, and in particular because of the lack of parallaxes. However, the use of this wealth of astrometric data comes with a specific challenge: how can the astrophysical parameters of interest be properly inferred from these data?\emph{Aims.{$<$}i/{$>$} The main focus of this paper, but not the only focus, is the issue of the estimation of distances from parallaxes, possibly combined with other information. We start with a critical review of the methods traditionally used to obtain distances from parallaxes and their shortcomings. Then we provide guidelines on how to use parallaxes more efficiently to estimate distances by using Bayesian methods. In particular we also show that negative parallaxes, or parallaxes with relatively large uncertainties still contain valuable information. Finally, we provide examples that show more generally how to use astrometric data for parameter estimation, including the combination of proper motions and parallaxes and the handling of covariances in the uncertainties.\emph{Methods.{$<$}i/{$>$} The paper contains examples based on simulated \emph{Gaia{$<$}i/{$>$} data to illustrate the problems and the solutions proposed. Furthermore, the developments and methods proposed in the paper are linked to a set of tutorials included in the \emph{Gaia{$<$}i/{$>$} archive documentation that provide practical examples and a good starting point for the application of the recommendations to actual problems. In all cases the source code for the analysis methods is provided.\emph{Results.{$<$}i/{$>$} Our main recommendation is to always treat the derivation of (astro-)physical parameters from astrometric data, in particular when parallaxes are involved, as an inference problem which should preferably be handled with a full Bayesian approach.\emph{Conclusions.{$<$}i/{$>$} \emph{Gaia{$<$}i/{$>$} will provide fundamental data for many fields of astronomy. Further data releases will provide more data, and more precise data. Nevertheless, to fully use the potential it will always be necessary to pay careful attention to the statistical treatment of parallaxes and proper motions. The purpose of this paper is to help astronomers find the correct approach.}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\IL7FYBZG\\Luri et al. - 2018 - Gaia Data Release 2 - Using Gaia parallaxes.pdf;C\:\\Users\\Emily\\Zotero\\storage\\6KCARVJY\\aa32964-18.html}}
@misc{lynga_open_1982, title = {Open {{Clusters}} in {{Our Galaxy}}}, author = {Lynga, G}, year = {1982}, urldate = {2019-09-19}, howpublished = {http://articles.adsabs.harvard.edu/pdf/1982A\%26A...109..213L}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6743H9NF\\1982A&A...109..pdf}}
@inproceedings{macqueen_methods_1967, title = {Some Methods for Classification and Analysis of Multivariate Observations}, booktitle = {"{{Proceedings}} of the {{Fifth Berkeley Symposium}} on {{Mathematical Statistics}} and {{Probability}}, {{Volume}} 1: {{Statistics}}"}, author = {MacQueen, J.}, year = {1967}, pages = {281--297}, publisher = {{The Regents of the University of California}}, issn = {0097-0433}, urldate = {2020-06-24}, abstract = {Project Euclid - mathematics and statistics online}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SQ8ITPIC\\1200512992.html}}
@article{malzer_hybrid_2019, title = {A {{Hybrid Approach To Hierarchical Density-based Cluster Selection}}}, author = {Malzer, Claudia and Baum, Marcus}, year = {2019}, month = dec, journal = {arXiv:1911.02282 [cs]}, eprint = {1911.02282}, primaryclass = {cs}, urldate = {2020-01-22}, abstract = {HDBSCAN is a density-based clustering algorithm that constructs a cluster hierarchy tree and then uses a specific stability measure to extract flat clusters from the tree. We propose an alternative method for selecting clusters from the HDBSCAN hierarchy. Our approach, HDBSCAN(\$\textbackslash hat\{\textbackslash epsilon\}\$), is particularly useful for data sets with variable densities where we require a low minimum cluster size but want to avoid an abundance of micro-clusters in high-density regions. The method uses an additional input parameter \$\textbackslash hat\{\textbackslash epsilon\}\$ and acts like a hybrid between DBSCAN* and HDBSCAN. It can easily be integrated into existing HDBSCAN implementations.}, archiveprefix = {arxiv}, keywords = {Computer Science - Databases}}
@article{mann_test_1947, title = {On a {{Test}} of {{Whether}} One of {{Two Random Variables}} Is {{Stochastically Larger}} than the {{Other}}}, author = {Mann, H. B. and Whitney, D. R.}, year = {1947}, journal = {The Annals of Mathematical Statistics}, volume = {18}, number = {1}, pages = {50--60}, publisher = {{Institute of Mathematical Statistics}}, issn = {00034851}, urldate = {2020-07-29}, abstract = {[Let x and y be two random variables with continuous cumulative distribution functions f and g. A statistic U depending on the relative ranks of the x's and y's is proposed for testing the hypothesis f = g. Wilcoxon proposed an equivalent test in the Biometrics Bulletin, December, 1945, but gave only a few points of the distribution of his statistic. Under the hypothesis f = g the probability of obtaining a given U in a sample of n x's and m y's is the solution of a certain recurrence relation involving n and m. Using this recurrence relation tables have been computed giving the probability of U for samples up to n = m = 8. At this point the distribution is almost normal. From the recurrence relation explicit expressions for the mean, variance, and fourth moment are obtained. The 2rth moment is shown to have a certain form which enabled us to prove that the limit distribution is normal if m, n go to infinity in any arbitrary manner. The test is shown to be consistent with respect to the class of alternatives \$f(x) {$>$} g(x)\$ for every x.]}}
@article{marigo_new_2017, title = {A {{NEW GENERATION OFPARSEC-COLIBRIS}}TEL{{LAR ISOCHRONES INCLUDING THE TP-AGB PHASE}}}, author = {Marigo, Paola and Girardi, L{\'e}o and Bressan, Alessandro and Rosenfield, Philip and Aringer, Bernhard and Chen, Yang and Dussin, Marco and Nanni, Ambra and Pastorelli, Giada and Rodrigues, Tha{\'i}se S. and Trabucchi, Michele and Bladh, Sara and Dalcanton, Julianne and Groenewegen, Martin A. T. and Montalb{\'a}n, Josefina and Wood, Peter R.}, year = {2017}, month = jan, journal = {The Astrophysical Journal}, volume = {835}, number = {1}, pages = {77}, issn = {0004-637X}, doi = {10.3847/1538-4357/835/1/77}, urldate = {2019-10-07}, abstract = {We introduce a new generation of PARSEC\textendash COLIBRI stellar isochrones that includes a detailed treatment of the thermally pulsing asymptotic giant branch (TP-AGB) phase, covering a wide range of initial metallicities (0.0001 {$<$} Zi {$<$} 0.06). Compared to previous releases, the main novelties and improvements are use of new TP-AGB tracks and related atmosphere models and spectra for M and C-type stars; inclusion of the surface H+He+CNO abundances in the isochrone tables, accounting for the effects of diffusion, dredge-up episodes and hot-bottom burning; inclusion of complete thermal pulse cycles, with a complete description of the in-cycle changes in the stellar parameters; new pulsation models to describe the long-period variability in the fundamental and first-overtone modes; and new dust models that follow the growth of the grains during the AGB evolution, in combination with radiative transfer calculations for the reprocessing of the photospheric emission. Overall, these improvements are expected to lead to a more consistent and detailed description of properties of TP-AGB stars expected in resolved stellar populations, especially in regard to their mean photometric properties from optical to mid-infrared wavelengths. We illustrate the expected numbers of TP-AGB stars of different types in stellar populations covering a wide range of ages and initial metallicities, providing further details on the ``C-star island'' that appears at intermediate values of age and metallicity, and about the AGB-boosting effect that occurs at ages close to 1.6-Gyr for populations of all metallicities. The isochrones are available through a new dedicated web server.}, langid = {english}, keywords = {Isochrones,Read}}
@article{marino_discovery_2018, title = {Discovery of {{Extended Main Sequence Turnoffs}} in {{Galactic Open Clusters}}}, author = {Marino, A. F. and Milone, A. P. and Casagrande, L. and Przybilla, N. and {Balaguer-N{\'u}{\~n}ez}, L. and Di Criscienzo, M. and Serenelli, A. and Vilardell, F.}, year = {2018}, month = aug, journal = {The Astrophysical Journal}, volume = {863}, pages = {L33}, issn = {0004-637X}, doi = {10.3847/2041-8213/aad868}, urldate = {2022-02-14}, abstract = {The color-magnitude diagrams (CMDs) of Galactic open clusters are widely considered to be the prototypes of single stellar populations. By using photometry in ultraviolet and optical bands we discovered that the nearby young cluster NGC 6705 (M11) exhibits an extended main-sequence turnoff (eMSTO) and a broadened main sequence (MS). This is the first evidence of multiple stellar populations in a Galactic open cluster. By using high-resolution Very Large Telescope (VLT) spectra we provide direct evidence that the multiple sequences along the CMD correspond to stellar populations with different rotation rates. Specifically, the blue MS (bMS) is formed of slow-rotating stars, while red-MS (rMS) stars are fast rotators. Moreover, we exploit photometry from Gaia data release 2 (DR2) to show that three Galactic open clusters, namely NGC 2099, NGC 2360, and NGC 2818, exhibit the eMSTO, thus suggesting that it is a common feature among these objects. Our previous work on the Large Magellanic Cloud star cluster NGC 1818 shows that slowly and rapidly rotating stars populate the bMS and rMS observed in its CMD. The similarities between M11 and the young clusters of the Magellanic Clouds (MCs) suggest that rotation is responsible for the appearance of multiple populations in the CMDs of both Milky Way open clusters and MCs young clusters.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Hertzsprung\textendash Russell and C\textendash M diagrams,NGC 2099,NGC 2360,NGC 2818,open clusters and associations: individual: NGC 6705}, annotation = {ADS Bibcode: 2018ApJ...863L..33M}}
@article{martinez-medina_response_2020, title = {On the Response of a Star Cluster to a Tidal Perturbation}, author = {{Martinez-Medina}, Luis A. and Gieles, Mark and Gnedin, Oleg Y. and Li, Hui}, year = {2020}, month = sep, journal = {arXiv:2009.06643 [astro-ph]}, eprint = {2009.06643}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {We study the response of star clusters to individual tidal perturbations using controlled \$N\$-body simulations. We consider perturbations by a moving point mass and by a disc, and vary the duration of the perturbation as well as the cluster density profile. For fast perturbations (i.e. `shocks'), the cluster gains energy in agreement with theoretical predictions in the impulsive limit. For slow disc perturbations, the energy gain is lower, and this has previously been attributed to adiabatic damping. However, the energy gain due to slow perturbations by a point-mass is similar to that due to fast shocks, which is not expected because adiabatic damping should be almost independent of the nature of the tides. We show that the geometric distortion of the cluster during slow perturbations is of comparable importance for the energy gain as adiabatic damping, and that the combined effect can qualitatively explain the results. The half-mass radius of the bound stars after a shock increases up to \$\textbackslash sim\$7\textbackslash\% for low-concentration clusters, and decreases \$\textbackslash sim\$3\textbackslash\% for the most concentrated ones. The fractional mass loss is a non-linear function of the energy gain, and depends on the nature of the tides and most strongly on the cluster density profile, making semi-analytic model predictions for cluster lifetimes extremely sensitive to the adopted density profile.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5F2VNJSU\\2009.html}}
@article{martocchia_leveraging_2020, title = {Leveraging {{HST}} with {{MUSE}}: {{II}}. {{Na-abundance}} Variations in Intermediate Age Star Clusters}, shorttitle = {Leveraging {{HST}} with {{MUSE}}}, author = {Martocchia, S. and Kamann, S. and Saracino, S. and Usher, C. and Bastian1, N. and Rejkuba, M. and Latour, M. and Lardo, C. and {Cabrera-Ziri}, I. and Dreizler, S. and Kacharov, N. and {Kozhurina-Platais}, V. and Larsen, S. and Mancino, S. and Platais, I. and Salaris, M.}, year = {2020}, month = sep, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2009.10023}, pages = {staa2929}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa2929}, urldate = {2020-10-07}, abstract = {Ancient (\${$>\$$}10 Gyr) globular clusters (GCs) show chemical abundance variations in the form of patterns among certain elements, e.g. N correlates with Na and anti-correlates with O. Recently, N abundance spreads have also been observed in massive star clusters that are significantly younger than old GCs, down to an age of \$\textbackslash sim\$2 Gyr. However, so far N has been the only element found to vary in such young objects. We report here the presence of Na abundance variations in the intermediate age massive star clusters NGC 416 (\$\textbackslash sim\$6.5 Gyr old) and Lindsay 1 (\$\textbackslash sim\$7.5 Gyr old) in the Small Magellanic Cloud, by combining HST and ESO-VLT MUSE observations. Using HST photometry we were able to construct ''chromosome maps'' and separate sub-populations with different N content, in the red giant branch of each cluster. MUSE spectra of individual stars belonging to each population were combined, resulting in high signal-to-noise spectra representative of each population, which were compared to search for mean differences in Na. We find a mean abundance variation of \$\textbackslash Delta\$[Na/Fe]\$=0.18\textbackslash pm0.04\$ dex for NGC 416 and \$\textbackslash Delta\$[Na/Fe]\$=0.24\textbackslash pm0.05\$ dex for Lindsay 1. In both clusters we find that the population that is enhanced in N is also enhanced in Na, which is the same pattern to the one observed in ancient GCs. Furthermore, we detect a bimodal distribution of core-helium burning Red Clump (RC) giants in the UV colour magnitude diagram of NGC 416. A comparison of the stacked MUSE spectra of the two RCs shows the same mean Na abundance difference between the two populations. The results reported in this work are a crucial hint that star clusters of a large age range share the same origin: they are the same types of objects, but only separated in age.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\R62XVLNV\\2009.html}}
@article{mcarthur_astrometry_2011, title = {Astrometry with the {{Hubble Space Telescope}}: {{Trigonometric Parallaxes}} of {{Selected Hyads}}}, shorttitle = {Astrometry with the {{Hubble Space Telescope}}}, author = {McArthur, Barbara E. and Benedict, G. Fritz and Harrison, Thomas E. and {van Altena}, William}, year = {2011}, month = may, journal = {The Astronomical Journal}, volume = {141}, pages = {172}, issn = {0004-6256}, doi = {10.1088/0004-6256/141/5/172}, urldate = {2022-03-29}, abstract = {We present absolute parallaxes and proper motions for seven members of the Hyades open cluster, pre-selected to lie in the core of the cluster. Our data come from archival astrometric data from fine guidance sensor (FGS) 3 and newer data for three Hyads from FGS 1r, both white-light interferometers on the Hubble Space Telescope (HST). We obtain member parallaxes from six individual FGS fields and use the field containing van Altena 622 and van Altena 627 (= HIP 21138) as an example. Proper motions, spectral classifications, and VJHK photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each Hyad. The parallax of vA 627 is significantly improved by including a perturbation orbit for this previously known spectroscopic binary, now an astrometric binary. Compared to our original (1997) determinations, a combination of new data, updated calibration, and improved analysis lowered the individual parallax errors by an average factor of 4.5. Comparing parallaxes of the four stars contained in the Hipparcos catalog, we obtain an average factor of 11 times improvement with the HST. With these new results, we also have better agreement with Hipparcos for the four stars in common. These new parallaxes provide an average distance for these seven members, langDrang = 47.5 pc, for the core, a {$\pm$}1{$\sigma$} dispersion depth of 3.6 pc, and a minimum depth from individual components of 16.0 {$\pm$} 0.9 pc. Absolute magnitudes for each member are compared to established main sequences with excellent agreement. We obtain a weighted average distance modulus for the core of the Hyades of m - M = 3.376 {$\pm$} 0.01, a value close to the previous Hipparcos values, m - M = 3.33 {$\pm$} 0.02. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.}, keywords = {astrometry,Astrophysics - Solar and Stellar Astrophysics,instrumentation: interferometers,parallaxes,proper motions,stars: distances,stars: individual: Hyades}, annotation = {ADS Bibcode: 2011AJ....141..172M}}
@article{mcinnes_accelerated_2017, title = {Accelerated {{Hierarchical Density Clustering}}}, author = {McInnes, Leland and Healy, John}, year = {2017}, month = nov, journal = {2017 IEEE International Conference on Data Mining Workshops (ICDMW)}, eprint = {1705.07321}, pages = {33--42}, doi = {10.1109/ICDMW.2017.12}, urldate = {2019-09-11}, abstract = {We present an accelerated algorithm for hierarchical density based clustering. Our new algorithm improves upon HDBSCAN*, which itself provided a significant qualitative improvement over the popular DBSCAN algorithm. The accelerated HDBSCAN* algorithm provides comparable performance to DBSCAN, while supporting variable density clusters, and eliminating the need for the difficult to tune distance scale parameter . This makes accelerated HDBSCAN* the default choice for density based clustering.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Statistics - Machine Learning}}
@article{mcinnes_hdbscan_2017, title = {Hdbscan: {{Hierarchical}} Density Based Clustering}, shorttitle = {Hdbscan}, author = {McInnes, Leland and Healy, John and Astels, Steve}, year = {2017}, month = mar, journal = {Journal of Open Source Software}, volume = {2}, number = {11}, pages = {205}, issn = {2475-9066}, doi = {10.21105/joss.00205}, urldate = {2020-06-03}, abstract = {McInnes et al, (2017), hdbscan: Hierarchical density based clustering, Journal of Open Source Software, 2(11), 205, doi:10.21105/joss.00205}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\FNVK9YAL\\joss.html}}
@inproceedings{mckinney_data_2010, title = {Data {{Structures}} for {{Statistical Computing}} in {{Python}}}, booktitle = {Proceedings of the 9th {{Python}} in {{Science Conference}}}, author = {McKinney, Wes}, year = {2010}, pages = {56--61}, address = {{Austin, Texas}}, doi = {10.25080/Majora-92bf1922-00a}, urldate = {2020-06-24}, abstract = {In this paper we are concerned with the practical issues of working with data sets common to finance, statistics, and other related fields. pandas is a new library which aims to facilitate working with these data sets and to provide a set of fundamental building blocks for implementing statistical models. We will discuss specific design issues encountered in the course of developing pandas with relevant examples and some comparisons with the R language. We conclude by discussing possible future directions for statistical computing and data analysis using Python.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\V7GTNACQ\\McKinney_2010_Data Structures for Statistical Computing in Python.pdf}}
@article{medina_revisited_2021, title = {A Revisited Study of {{Cepheids}} in Open Clusters in the {{Gaia}} Era}, author = {Medina, Gustavo E. and Lemasle, Bertrand and Grebel, Eva K.}, year = {2021}, month = apr, journal = {arXiv:2104.14565 [astro-ph]}, eprint = {2104.14565}, primaryclass = {astro-ph}, urldate = {2021-05-04}, abstract = {In this paper we revisit the problem of identifying bona fide cluster Cepheids by performing an all-sky search for Cepheids associated with open clusters and making use of state-of-the-art catalogued information for both Cepheids and clusters, based on the unparalleled astrometric precision of the second and early third data releases of the Gaia satellite. We determine membership probabilities by following a Bayesian approach using spatial and kinematic information of the potential cluster-Cepheid pairs. We confirm 19 Cepheid-cluster associations considered in previous studies as bona-fide, and question the established cluster membership of six other associations. In addition, we identify 138 cluster Cepheid candidates of potential interest, mostly in recently discovered open clusters. We report on at least two new clusters possibly hosting more than one Cepheid. Furthermore, we explore the feasibility of using open clusters hosting Cepheids to empirically determine the Cepheid period-age relation through the use of Gaia and 2MASS photometry and a semi-automated method to derive cluster ages. We conclude that the usage of cluster Cepheids as tentative probes of the period-age relations still faces difficulties due to the sparsely populated red giant branch and the stochastically sampled main-sequence turn-off of the open clusters, making age determinations a challenging task. This biases the age-dateable cluster selection for Cepheid period-age studies towards older and high-mass clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{meibom_stellar_2008, title = {Stellar {{Ages}} from {{Stellar Rotation}}}, author = {Meibom, Soren}, year = {2008}, month = oct, journal = {Proceedings of the International Astronomical Union}, volume = {4}, number = {S258}, eprint = {0812.5078}, pages = {357--362}, issn = {1743-9213, 1743-9221}, doi = {10.1017/S1743921309032013}, urldate = {2019-10-25}, abstract = {Our ability to determine stellar ages from measurements of stellar rotation, hinges on how well we can measure the dependence of rotation on age for stars of different masses. Rotation periods for stars in open clusters are essential to determine the relations between stellar age, rotation, and mass (color). Until recently, ambiguities in vsini data and lack of cluster membership information, prevented a clear empirical definition of the dependence of rotation on color. Direct measurements of stellar rotation periods for members in young clusters have now revealed a well-defined period-color relation. We show new results for the open clusters M35 and M34. However, rotation periods based on ground-based observations are limited to young clusters. The Hyades represent the oldest coeval population of stars with measured rotation periods. Measurements of rotation periods for older stars are needed to properly constrain the dependence of stellar rotation on age. We present our plans to use the Kepler space telescope to measure rotation periods in clusters as old as and older than the Sun.}, archiveprefix = {arxiv}, keywords = {ages,Astrophysics,review,stars,stellar rotation}, file = {C\:\\Users\\Emily\\Zotero\\storage\\I86WZGSV\\0812.html}}
@article{meingast_extended_2019, title = {Extended Stellar Systems in the Solar Neighborhood . {{II}}. {{Discovery}} of a Nearby 120\textdegree{} Stellar Stream in {{Gaia DR2}}}, author = {Meingast, Stefan and Alves, Jo{\~a}o and F{\"u}rnkranz, Verena}, year = {2019}, month = feb, journal = {Astronomy and Astrophysics}, volume = {622}, pages = {L13}, doi = {10.1051/0004-6361/201834950}, urldate = {2019-10-21}, abstract = {We report the discovery of a large, dynamically cold, coeval stellar stream that is currently traversing the immediate solar neighborhood at a distance of only 100 pc. The structure was identified in a wavelet decomposition of the 3D velocity space of all stars within 300 pc of the Sun. Its members form a highly elongated structure with a length of at least 400 pc, while its vertical extent measures only about 50 pc. Stars in the stream are not isotropically distributed but instead form two parallel lanes with individual local overdensities, that may correspond to a remnant core of a tidally disrupted cluster or OB association. Its members follow a very well-defined main sequence in the observational Hertzsprung-Russel diagram and also show a remarkably low 3D velocity dispersion of only 1.3 km s\textsuperscript{-1}. These findings strongly suggest a common origin as a single coeval stellar population. An extrapolation of the present-day mass function indicates a total mass of at least 2000 M\textsubscript{{$\Sun$}}, making it larger than most currently known clusters or associations in the solar neighborhood. We estimated the age of the stream to be around 1 Gyr based on a comparison with a set of isochrones and giant stars in our member selection and find a mean metallicity of [Fe/H] = -0.04. This structure may very well represent the Galactic disk counterpart to the prominent stellar streams observed in the Milky Way halo. As such, it constitutes a new valuable probe to constrain the Galaxy's mass distribution. Full Table A.1 is only available at the CDS via anonymous ftp to {$<$}A href="http://cdsarc.u-strasbg.fr/"{$>$}http://cdsarc.u-strasbg.fr{$<$}/A{$>$} (ftp://130.79.128.5) or via {$<$}A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/L13"{$>$}http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/L13{$<$}/A{$>$}}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\BYTG9A53\\abstract.html}}
@article{meingast_extended_2021, title = {Extended Stellar Systems in the Solar Neighborhood -- {{V}}. {{Discovery}} of Coronae of Nearby Star Clusters}, author = {Meingast, Stefan and Alves, Jo{\~a}o and Rottensteiner, Alena}, year = {2021}, journal = {Astronomy \& Astrophysics}, volume = {645}, pages = {A84}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202038610}, urldate = {2020-10-15}, abstract = {In this paper, we present a novel view on the morphology and the dynamical state of 10 prominent, nearby (\$\textbackslash leq\$ 500 pc), and young (\$\textbackslash sim\$30-300 Myr) open star clusters with Gaia DR2: \$\textbackslash alpha\textbackslash,\$Per, Blanco 1, IC 2602, IC 2391, Messier 39, NGC 2451A, NGC 2516, NGC 2547, Platais 9, and the Pleiades. We introduce a pioneering member identification method that is informed by cluster bulk velocities and deconvolves the spatial distribution with a mixture of Gaussians. Our approach enables inferring the clusters' true spatial distribution by effectively filtering field star contaminants while at the same time mitigating the impact of positional errors along the line of sight. This first application of the method reveals the existence of vast stellar coronae, extending for \$\textbackslash gtrsim\textbackslash,\$100 pc and surrounding the, by comparison tiny and compact, cluster cores. The coronae and cores form intertwined, co-eval, and co-moving extended cluster populations, each encompassing tens of thousands of cubic parsec and stretching across tens of degrees on the sky. Our analysis shows that the coronae are gravitationally unbound but largely comprise the bulk of the populations' stellar mass. Most systems are in a highly dynamic state, showing evidence of expansion and sometimes simultaneous contraction along different spatial axes. The velocity field of the extended populations for the cluster cores appears asymmetric but is aligned along a spatial axis unique to each cluster. The overall spatial distribution and the kinematic signature of the populations are largely consistent with the differential rotation pattern of the Milky Way. This finding underlines the important role of global Galactic dynamics to the fate of stellar systems. Our results highlight the complexity of the Milky Way's open cluster population and call for a new perspective on the characterization and dynamical state of open clusters.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NJ6M92RV\\2010.html}}
@article{meingast_extended_stellar_2019, title = {Extended Stellar Systems in the Solar Neighborhood. {{I}}. {{The}} Tidal Tails of the {{Hyades}}}, author = {Meingast, Stefan and Alves, Jo{\~a}o}, year = {2019}, month = jan, volume = {621}, eprint = {1811.04931}, primaryclass = {astro-ph.GA}, pages = {L3}, doi = {10.1051/0004-6361/201834622}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: individual: Hyades,stars: kinematics and dynamics}}
@article{meng_tidal_2022, title = {Tidal Disruption of Star Clusters in Galaxy Formation Simulations}, author = {Meng, Xi and Gnedin, Oleg Y.}, year = {2022}, month = jan, journal = {arXiv:2201.09826 [astro-ph]}, eprint = {2201.09826}, primaryclass = {astro-ph}, urldate = {2022-01-26}, abstract = {We investigate the evolution of the tidal field experienced by massive star clusters using cosmological simulations of Milky Way-sized galaxies. Clusters in our simulations experience the strongest tidal force in the first few hundred Myr after formation, when the maximum eigenvalue of the tidal tensor reaches several times 104 Gyr-2. After about 1 Gyr the tidal field plateaus at a lower value, with the median {$\mathsl{\lambda}$}m {$\sim$} 3 \texttimes{} 103 Gyr-2. The fraction of time clusters spend in high tidal strength ({$\mathsl{\lambda}$}m {$>$} 3 \texttimes{} 104 Gyr-2) regions also decreases with their age from {$\sim$}20\% immediately after formation to less than 1\% after 1 Gyr. At early ages both the in situ and ex situ clusters experience similar tidal fields, while at older ages the in situ clusters in general experience stronger tidal field due to their lower orbits in host galaxy. This difference is reflected in the survival of clusters: we looked into cluster disruption calculated in simulation runtime and found that ex situ star clusters of the same initial mass typically end up with higher bound fraction at the last available simulation snapshot than the in situ ones.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5XZ3TVVG\\Meng and Gnedin - 2022 - Tidal disruption of star clusters in galaxy format.pdf}}
@article{menon_dependence_2021, title = {The {{Dependence}} of the {{Hierarchical Distribution}} of {{Star Clusters}} on {{Galactic Environment}}}, author = {Menon, Shyam H. and Grasha, Kathryn and Elmegreen, Bruce G. and Federrath, Christoph and Krumholz, Mark R. and Calzetti, Daniela and S{\'a}nchez, N{\'e}stor and Linden, Sean T. and Adamo, Angela and Messa, Matteo and Cook, David O. and Dale, Daniel A. and Grebel, Eva K. and Fumagalli, Michele and Sabbi, Elena and Johnson, Kelsey E. and Smith, Linda J. and Kennicutt, Robert C.}, year = {2021}, month = aug, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2108.04387}, pages = {stab2413}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stab2413}, urldate = {2021-09-15}, abstract = {We use the angular Two Point Correlation Function (TPCF) to investigate the hierarchical distribution of young star clusters in 12 local (3--18 Mpc) star-forming galaxies using star cluster catalogues obtained with the \textbackslash textit\{Hubble Space Telescope\} (\textbackslash textit\{HST\}) as part of the Treasury Program LEGUS (Legacy ExtraGalactic UV Survey). The sample spans a range of different morphological types, allowing us to infer how the physical properties of the galaxy affect the spatial distribution of the clusters. We also prepare a range of physically motivated toy models to compare with and interpret the observed features in the TPCFs. We find that, conforming to earlier studies, young clusters (\$T \textbackslash la 10\textbackslash, \textbackslash mathrm\{Myr\}\$) have power-law TPCFs that are characteristic of fractal distributions with a fractal dimension \$D\_2\$, and this scale-free nature extends out to a maximum scale \$l\_\{\textbackslash mathrm\{corr\}\}\$ beyond which the distribution becomes Poissonian. However, \$l\_\{\textbackslash mathrm\{corr\}\}\$, and \$D\_2\$ vary significantly across the sample, and are correlated with a number of host galaxy physical properties, suggesting that there are physical differences in the underlying star cluster distributions. We also find that hierarchical structuring weakens with age, evidenced by flatter TPCFs for older clusters (\$T \textbackslash ga 10\textbackslash, \textbackslash mathrm\{Myr\}\$), that eventually converges to the residual correlation expected from a completely random large-scale radial distribution of clusters in the galaxy in \$\textbackslash sim 100 \textbackslash, \textbackslash mathrm\{Myr\}\$. Our study demonstrates that the hierarchical distribution of star clusters evolves with age, and is strongly dependent on the properties of the host galaxy environment.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\RITAEC3U\\2108.html}}
@incollection{mermilliod_database_1995, title = {The {{Database}} for {{Galactic Open Clusters}} ({{BDA}})}, booktitle = {Information \textbackslash\& {{On-Line Data}} in {{Astronomy}}}, author = {Mermilliod, J.-C.}, year = {1995}, volume = {203}, pages = {127--138}, publisher = {{Springer Netherlands}}, urldate = {2020-06-24}, abstract = {The database for stars in galactic open clusters (BDA) has been developed since 1987 at the Institute for Astronomy, University of Lausanne. The extensive collection covers data for about 100,000 stars in some 500 NGC, IC, and anonymous clusters. It includes measurements in most photometric systems in which cluster stars have been observed, spectroscopic observations, astrometric data, and extensive bibliography. The author describes the organisation of the data, the facilities offered by the database, and presently available access modes.}, keywords = {Data Bases: Open Clusters}}
@article{messina_constraining_2020, title = {Constraining the Age of Young Stellar Clusters via the Amplitude of Photometric Variability}, author = {Messina, Sergio}, year = {2020}, month = dec, journal = {arXiv:2011.13640 [astro-ph]}, eprint = {2011.13640}, primaryclass = {astro-ph}, urldate = {2021-01-05}, abstract = {Determination of stellar age is a crucial task in astrophysics research. Different methods are nowadays used either model dependent or based on calibrated empirical relations. The most reliable results are generally obtained when different methods are used in complementary way. We propose a new method for the age determination of young stellar associations and open clusters (ages {$<$} 125 Myr), which can allow to further constrain the age when used together with other methods. We explore the amplitude of the photometric variability in bins of color and rotation period of five young associations and clusters spanning an interval of ages from 1-3 Myr to 625 Myr (Taurus, rho Ophiuchi, Upper Scorpius, Pleiades, and Praesepe), which all have high-quality time-series photometry from Kepler K2 campaigns. In the low-mass regime, we find that stars with similar color and rotation period but different ages exhibit different amplitudes of their photometric variability, with younger stars showing a larger photometric variability than older stars. The decline of photometric variability amplitude versus age in stars with similar color and rotation period can be in principle calibrated and be adopted as an additional empirical relation to constrain the age of young associations and open clusters, provided that time-series photometry is available for their low-mass members.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\FV5JNFVX\\2011.html}}
@misc{milone_multiple_2022, title = {Multiple {{Populations}} in {{Star Clusters}}}, author = {Milone, Antonino P. and Marino, Anna F.}, year = {2022}, month = jun, number = {arXiv:2206.10564}, eprint = {2206.10564}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2206.10564}, urldate = {2022-06-27}, abstract = {We review the multiple population (MP) phenomenon of globular clusters (GCs): i.e., the evidence that GCs typically host groups of stars with different elemental abundances and/or distinct sequences in photometric diagrams. Most Galactic and extragalactic clusters exhibit internal variations of He, C, N, O, Na, and Al. They host two distinct stellar populations: the first population of stars, which resemble field stars with similar metallicities, and one or more second stellar populations that show the signature of high-temperature H-burning. In addition, a sub-sample of clusters hosts stellar populations with different heavy-element abundances. The MP origin remains one of the most puzzling, open issues of stellar astrophysics. We summarize the scenarios for the MP formation and depict the modern picture of GCs and their stellar populations along with the main evolutionary phases. We show that the MP behavior dramatically changes from one cluster to another and investigate their complexity to define common properties. We investigate relations with the host galaxy, the parameters of the host clusters (e.g., GC's mass, age, orbit), and stellar mass. We summarize results on spatial distribution and internal kinematics of MPs. Finally, we review the relation between MPs and the so-called second-parameter problem of the horizontal-branch morphology of GCs and summarize the main findings on the extended main-sequence phenomenon in young clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{minniti_discovery_2021, title = {Discovery of a New Nearby Globular Cluster with Extreme Kinematics Located in the Extension of a Halo Stream}, author = {Minniti, Dante and {Fern{\'a}ndez-Trincado}, Jos{\'e} G. and G{\'o}mez, Mat{\'i}as and Smith, Leigh C. and Lucas, Philip W. and Ramos, R. Contreras}, year = {2021}, month = jun, journal = {arXiv:2106.01383 [astro-ph]}, eprint = {2106.01383}, primaryclass = {astro-ph}, urldate = {2021-06-07}, abstract = {Context. We report the discovery of VVV-CL160, a new nearby globular cluster (GC) with extreme kinematics, located in the Galactic plane at \$l = 10.1477\$ deg, \$b = 0.2999\$ deg. Aims. We aim to characterize the physical properties of this new GC and place it in the context of the Milky Way, exploring its possible connection with the known GC NGC 6544 and with the Hrid halo stream. Methods. VVV-CL160 was originally detected in the VISTA Variables in the V\textbackslash 'ia L\textbackslash 'actea (VVV) survey. We use the proper motions (PMs) from the updated VVV Infrared Astrometric Catalog (VIRAC2) to select GC members and make deep near-infrared color-magnitude diagrams (CMDs) to study the cluster properties. We also fit King models to the decontaminated sample to determine the GC structural parameters. Results. VVV-CL160 has an unusually large PM for a Galactic GC as measured with VIRAC2 and Gaia EDR3: \$\textbackslash mu\_\{\textbackslash alpha\}\textbackslash cos(\textbackslash delta)\$ = \$-2.3 \textbackslash pm 0.1 \$ mas yr\$\^\{-1\}\$ and \$\textbackslash mu\_\{\textbackslash delta\}\$ = \$-16.8 \textbackslash pm 0.1 \$ mas yr\$\^\{-1\}\$. The kinematics are similar to those of the known GC NGC 6544 and the Hrid halo stream. We estimate a reddening of \$E(J-K) = 1.95\$ mag and an extinction of \$A\_\{k\}= 1.40\$ mag for VVV-CL160. We also measure a distance modulus of \$(m-M) = 13.01\$ mag and a distance of \$D\_\{\textbackslash odot\} = 4.0 \textbackslash pm 0.5\$ kpc. This places the GC at \$z=29\$ pc above the Galactic plane and at a galactocentric distance of \$R\_G=4.2\$ kpc. We also measure a metallicity of \$[Fe/H] = -1.4 \textbackslash pm 0.2\$ dex for an adopted age of \$t=12\$ Gyr; King model fits of the PM-decontaminated sample reveal a concentrated GC, with core radius \$r\_\{c\}= 22.8"\$ and tidal radius \$r\_\{t\}= 50'\$. .... We also explore the possible association of this new GC with other GCs and halo streams. Conclusions. Based on the locations and kinematics, we suggest that VVV-CL160, along with NGC 6544, may be associated with the extension of the Hrid halo stream.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\AY8C655R\\2106.html}}
@article{miocchi_star_2013, title = {Star Count Density Profiles and Structural Parameters of 26 {{Galactic}} Globular Clusters}, author = {Miocchi, P. and Lanzoni, B. and Ferraro, F. R. and Dalessandro, E. and Vesperini, E. and Pasquato, M. and Beccari, G. and Pallanca, C. and Sanna, N.}, year = {2013}, month = aug, journal = {The Astrophysical Journal}, volume = {774}, number = {2}, eprint = {1307.6035}, pages = {151}, issn = {0004-637X, 1538-4357}, doi = {10.1088/0004-637X/774/2/151}, urldate = {2021-11-04}, abstract = {We used a proper combination of high-resolution HST observations and wide-field ground based data to derive the radial star density profile of 26 Galactic globular clusters from resolved star counts (which can be all freely downloaded on-line). With respect to surface brightness (SB) profiles (which can be biased by the presence of sparse, bright stars), star counts are considered to be the most robust and reliable tool to derive cluster structural parameters. For each system a detailed comparison with both King and Wilson models has been performed and the most relevant best-fit parameters have been obtained. This is the largest homogeneous catalog collected so far of star count profiles and structural parameters derived therefrom. The analysis of the data of our catalog has shown that: (1) the presence of the central cusps previously detected in the SB profiles of NGC 1851, M13 and M62 is not confirmed; (2) the majority of clusters in our sample are fitted equally well by the King and the Wilson models; (3) we confirm the known relationship between cluster size (as measured by the effective radius) and galactocentric distances; (4) the ratio between the core and the effective radii shows a bimodal distribution, with a peak at {$\sim$} 0.3 for about 80\% of the clusters, and a secondary peak at {$\sim$} 0.6 for the remaining 20\%. Interestingly, the main peak turns out to be in agreement with what expected from simulations of cluster dynamical evolution and the ratio between these two radii well correlates with an empirical dynamical age indicator recently defined from the observed shape of blue straggler star radial distribution, thus suggesting that no exotic mechanisms of energy generation are needed in the cores of the analyzed clusters.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\7PVA4WEC\\Miocchi et al. - 2013 - Star count density profiles and structural paramet.pdf}}
@article{mishenina_molybdenum_2020, title = {Molybdenum in the Open Cluster Stars}, author = {Mishenina and Tamara and Shereta and Elena and Pignatari and Marco and Carraro and Giovanni and Gorbaneva and Tatyana and Soubiran and Caroline}, year = {2020}, month = jun, journal = {arXiv:2006.04629 [astro-ph]}, eprint = {2006.04629}, primaryclass = {astro-ph}, urldate = {2020-06-09}, abstract = {Molybdenum abundances in the stars from 13 different open clusters were determined. High-resolution stellar spectra were obtained using the VLT telescope equipped with the UVES spectrograph on Cerro Paranal, Chile. The Mo abundances were derived in the LTE approximation from the Mo I lines at 5506 A and 5533 A. A comparative analysis of the behaviour of molybdenum in the sampled stars of open clusters and Galactic disc show similar trends of decreasing Mo abundances with increasing metallicities; such a behaviour pattern suggests a common origin of the examined populations. On the other hand, the scatter of Mo abundances in the open cluster stars is slightly greater, 0.14 dex versus 0.11 dex. The results are discussed, considering the abundance trends with the age of clusters and distances from the center of the Galaxy.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\DIBZ99LD\\2006.html}}
@article{moe_mind_2017, title = {Mind Your {{Ps}} and {{Qs}}: The {{Interrelation}} between {{Period}} ({{P}}) and {{Mass-ratio}} ({{Q}}) {{Distributions}} of {{Binary Stars}}}, shorttitle = {Mind Your {{Ps}} and {{Qs}}}, author = {Moe, Maxwell and Di Stefano, Rosanne}, year = {2017}, month = may, journal = {arXiv:1606.05347 [astro-ph]}, eprint = {1606.05347}, primaryclass = {astro-ph}, doi = {10.3847/1538-4365/aa6fb6}, urldate = {2022-03-24}, abstract = {We compile observations of early-type binaries identified via spectroscopy, eclipses, long-baseline interferometry, adaptive optics, common proper motion, etc. Each observational technique is sensitive to companions across a narrow parameter space of orbital periods P and mass ratios q = M\_comp/M\_1. After combining the samples from the various surveys and correcting for their respective selection effects, we find the properties of companions to O-type and B-type main-sequence (MS) stars differ among three regimes. First, at short orbital periods P {$<$} 20 days (separations a {$<$} 0.4 AU), the binaries have small eccentricities e {$<$} 0.4, favor modest mass ratios {$<$}q{$>$} = 0.5, and exhibit a small excess of twins q {$>$} 0.95. Second, the companion frequency peaks at intermediate periods log P (days) = 3.5 (a = 10 AU), where the binaries have mass ratios weighted toward small values q = 0.2-0.3 and follow a Maxwellian "thermal" eccentricity distribution. Finally, companions with long orbital periods log P (days) = 5.5-7.5 (a = 200-5,000 AU) are outer tertiary components in hierarchical triples, and have a mass ratio distribution across q = 0.1-1.0 that is nearly consistent with random pairings drawn from the initial mass function. We discuss these companion distributions and properties in the context of binary star formation and evolution. We also reanalyze the binary statistics of solar-type MS primaries, taking into account that (30+/-10)\% of single-lined spectroscopic binaries likely contain white dwarf companions instead of low-mass stellar secondaries. The mean frequency of stellar companions with q {$>$} 0.1 and log P (days) {$<$} 8.0 per primary increases from 0.50+/-0.04 for solar-type MS primaries to 2.1+/-0.3 for O-type MS primaries. We fit joint probability density functions f(M\_1,q,P,e) to the corrected distributions, which can be incorporated into binary population synthesis studies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}}
@article{moitinho_ccd_1997, title = {{{CCD UBV Photometry}} of the {{Young Open Cluster NGC}} 3766}, author = {Moitinho, Andre and Alfaro, Emilio J. and Yun, Joao Lin and Phelps, Randy L.}, year = {1997}, month = apr, journal = {The Astronomical Journal}, volume = {113}, pages = {1359}, issn = {00046256}, doi = {10.1086/118349}, urldate = {2019-09-30}, abstract = {NGC 3766 is a young open cluster, located in the Carina complex, which contains an unusually large number of Be stars. This fact makes it specially interesting for providing observational constraints for the Be phenomenon. We have obtained UBV photometry for this cluster using a mosaic of CCD images centered around the cluster field, resulting in the deepest color-magnitude diagram of NGC 3766 obtained so far. The analysis of the photometric diagrams yielded a reddening of E(5 \textemdash{} V) = 0.20{$\pm$}0.10, a distance modulus of (m \textemdash M)0= 11.73{$\pm$}0.33 and an age of about 24 Myr. The luminosity function was derived by using the photometry of a nearby star field to remove field contamination from the cluster sample. The slope of the mass function was found to be F = - 1.41 {$\pm$}0.08 in the range 2.5}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6US4P6LP\\Moitinho et al_1997_CCD UBV Photometry of the Young Open Cluster NGC 3766.pdf}}
@article{monteiro_distances_2019, title = {Distances and Ages from Isochrone Fits of 150 Open Clusters Using {{Gaia DR2}} Data}, author = {Monteiro, H. and Dias, W. S.}, year = {2019}, month = aug, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {487}, number = {2}, pages = {2385--2406}, issn = {0035-8711}, doi = {10.1093/mnras/stz1455}, urldate = {2019-09-06}, abstract = {ABSTRACT. We investigate a sample of open cluster candidates with no previous age determination using astrometric and photometric data from the Gaia DR2 catalo}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\AZYP8GAV\\Monteiro_Dias_2019_Distances and ages from isochrone fits of 150 open clusters using Gaia DR2 data.pdf;C\:\\Users\\Emily\\Zotero\\storage\\4C2EKCUC\\5499320.html}}
@article{monteiro_distribution_2021, title = {The Distribution of Open Clusters in the {{Galaxy}}}, author = {Monteiro, H. and Barros, D. A. and Dias, W. S. and L{\'e}pine, J. R. D.}, year = {2021}, month = mar, journal = {arXiv:2104.00134 [astro-ph]}, eprint = {2104.00134}, primaryclass = {astro-ph}, urldate = {2021-04-20}, abstract = {In this work we explore the new catalog of galactic open clusters that became available recently, containing 1750 clusters that have been re-analysed using the Gaia DR2 catalog to determine the stellar memberships. We used the young open clusters as tracers of spiral arms and determined the spiral pattern rotation speed of the Galaxy and the corotation radius, the strongest Galactic resonance. The sample of open clusters used here increases the last one from Dias et al. (2019) used in the previous determination of the pattern speed by dozens objects. In addition, the distances and ages values are better determined, using improvements to isochrone fitting and including an updated extinction polynomial for the Gaia DR2 photometric band-passes, and the Galactic abundance gradient as a prior for metallicity. In addition to the better age determinations, the catalog contains better positions in the Galactic plane and better proper motions. This allow us to discuss not only the present space distribution of the clusters, but also the space distribution of the clusters's birthplaces, obtained by integration of the orbits for a time equal to their age. The value of the rotation velocity of the arms (\$28.5 \textbackslash pm 1.0\$ km s\$\^\{-1\}\$ kpc\$\^\{-1\}\$) implies that the corotation radius (\$R\_c\$) is close to the solar Galactic orbit (\$R\_c/R\_0 = 1.01\textbackslash pm0.08\$), which is supported by other observational evidence discussed in this text. A simulation is presented, illustrating the motion of the clusters in the reference frame of corotation. We also present general statistics of the catalog of clusters, like spatial distribution, distribution relative to height from the Galactic plane, and distribution of ages and metallicity. An important feature of the space distribution, the corotation gap in the gas distribution and its consequences for the young clusters, is discussed.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\BQU2D7PH\\2104.html}}
@article{monteiro_fitting_2010, title = {Fitting Isochrones to Open Cluster Photometric Data - {{A}} New Global Optimization Tool}, author = {Monteiro, H. and Dias, W. S. and Caetano, T. C.}, year = {2010}, month = jun, journal = {Astronomy \& Astrophysics}, volume = {516}, pages = {A2}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/200913677}, urldate = {2019-09-30}, abstract = {We present a new technique to fit color\textendash magnitude diagrams of open clusters based on the cross-entropy global optimization algorithm. The method uses theoretical isochrones available in the literature and maximizes a weighted likelihood function based on distances measured in the color\textendash magnitude space. The weights are obtained through a non parametric technique that takes into account the star distance to the observed center of the cluster, observed magnitude uncertainties, the stellar density profile of the cluster among others. The parameters determined simultaneously are distance, reddening, age and metallicity. The method takes binary fraction into account and uses a Monte-Carlo approach to obtain uncertainties on the determined parameters for the cluster by running the fitting algorithm many times with a re-sampled data set through a bootstrapping procedure. We present results for 9 well studied open clusters, based on 15 distinct data sets, and show that the results are consistent with previous studies. The method is shown to be reliable and free of the subjectivity of most previous visual isochrone fitting techniques.}, copyright = {\textcopyright{} ESO, 2010}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\DR2XRV4T\\aa13677-09.html}}
@article{monteiro_fundamental_2020, title = {Fundamental Parameters for 45 Open Clusters with {{Gaia DR2}}, an Improved Extinction Correction and a Metallicity Gradient Prior}, author = {Monteiro, H. and Dias, W. S. and Moitinho, A. and {Cantat-Gaudin}, T. and L{\'e}pine, J. R. D. and Carraro, G. and Paunzen, E.}, year = {2020}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {499}, pages = {1874--1889}, issn = {0035-8711}, doi = {10.1093/mnras/staa2983}, urldate = {2022-01-20}, abstract = {Reliable fundamental parameters of open clusters (OCs) such as distance, age, and extinction are key to our understanding of Galactic structure and stellar evolution. In this work, we use Gaia Data Release 2 (DR2) to investigate 45 OCs listed in the New catalogue of optically visible open clusters and candidates (DAML) but with no previous astrometric membership estimation based on Gaia DR2. In the process of selecting targets for this study, we found that some clusters reported as new discoveries in recent papers based on Gaia DR2 were already known clusters listed in DAML. Cluster memberships were determined using a maximum likelihood method applied to Gaia DR2 astrometry. This has allowed us to estimate mean proper motions and mean parallaxes for all investigated clusters. Mean radial velocities were also determined for 12 clusters, 7 of which had no previous published values. We have improved our isochrone fitting code to account for interstellar extinction using an updated extinction polynomial for the Gaia DR2 photometric bandpasses and the Galactic abundance gradient as a prior for metallicity. The updated procedure was validated with a sample of clusters with high-quality [Fe/H] determinations. We then did a critical review of the literature and verified that our cluster parameter determinations represent a substantial improvement over previous values.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general}, annotation = {ADS Bibcode: 2020MNRAS.499.1874M}}
@inproceedings{moulavi_density-based_2014, title = {Density-{{Based Clustering Validation}}}, booktitle = {Proceedings of the 2014 {{SIAM International Conference}} on {{Data Mining}}}, author = {Moulavi, Davoud and Jaskowiak, Pablo A. and Campello, Ricardo J. G. B. and Zimek, Arthur and Sander, J{\"o}rg}, year = {2014}, month = apr, pages = {839--847}, publisher = {{Society for Industrial and Applied Mathematics}}, doi = {10.1137/1.9781611973440.96}, urldate = {2020-01-31}, abstract = {One of the most challenging aspects of clustering is validation, which is the objective and quantitative assessment of clustering results. A number of different relative validity criteria have been proposed for the validation of globular, clusters. Not all data, however, are composed of globular clusters. Density-based clustering algorithms seek partitions with high density areas of points (clusters, not necessarily globular) separated by low density areas, possibly containing noise objects. In these cases relative validity indices proposed for globular cluster validation may fail. In this paper we propose a relative validation index for density-based, arbitrarily shaped clusters. The index assesses clustering quality based on the relative density connection between pairs of objects. Our index is formulated on the basis of a new kernel density function, which is used to compute the density of objects and to evaluate the within- and between-cluster density connectedness of clustering results. Experiments on synthetic and real world data show the effectiveness of our approach for the evaluation and selection of clustering algorithms and their respective appropriate parameters.}, isbn = {978-1-61197-344-0}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\BJUZ6ZBG\\Moulavi et al_2014_Density-Based Clustering Validation.pdf}}
@article{mozel_sky_disk_2003, title = {The Sky Disk of Nebra}, author = {Mozel, Philip}, year = {2003}, month = oct, journal = {Journal of the Royal Astronomical Society of Canada}, volume = {97}, number = {5}, pages = {245}}
@article{naylor_maximum-likelihood_2006, title = {A Maximum-Likelihood Method for Fitting Colour\textendash Magnitude Diagrams}, author = {Naylor, Tim and Jeffries, R. D.}, year = {2006}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {373}, number = {3}, pages = {1251--1263}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2006.11099.x}, urldate = {2019-09-30}, abstract = {Abstract. We present a maximum-likelihood method for fitting two-dimensional model distributions to stellar data in colour\textendash magnitude space. This allows one to}, langid = {english}}
@article{negueruela_cluster_2020, title = {Cluster Membership for the Long Period {{Cepheid}} Calibrator {{SV Vul}}}, author = {Negueruela, Ignacio and Dorda, Ricardo and Marco, Amparo}, year = {2020}, month = mar, journal = {arXiv:2003.10946 [astro-ph]}, eprint = {2003.10946}, primaryclass = {astro-ph}, urldate = {2020-03-25}, abstract = {Classical Cepheids represent the first step of the distance scale ladder. Claims of tension between the locally calculated Hubble constant and the values deduced from \$Planck\$'s results have sparked new interest in these distance calibrators. Cluster membership provides an independent distance measurement, as well as astrophysical context for studies of their stellar properties. Here we report the discovery of a young open cluster in the vicinity of SV Vul, one of the most luminous Cephedis known in the Milky Way. \$Gaia\$ DR2 data show that SV Vul is a clear astrometric and photometric member of the new cluster, which we name Alicante 13. Although dispersed, Alicante 13 is moderately well populated, and contains three other luminous stars, one early-A bright giant and two low-luminosity red supergiants. The cluster is about 30 Ma old at a nominal distance of 2.5 kpc. With this age, SV Vul should have a mass around \$10\textbackslash :\$M\$\_\{\textbackslash odot\}\$, in good accordance with its luminosity, close to the highest luminosity for Cepheids allowed by recent stellar models.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\U9BHL28P\\2003.html}}
@article{negueruela_massive_2021, title = {A Massive Open Cluster Hiding in Full Sight}, author = {Negueruela, Ignacio and Chen{\'e}, Andr{\'e}-Nicolas and Tabernero, Hugo M. and Dorda, Ricardo and Borissova, Jura and Marco, Amparo and Kurtev, Radostin}, year = {2021}, month = apr, journal = {arXiv:2104.08778 [astro-ph]}, eprint = {2104.08778}, primaryclass = {astro-ph}, urldate = {2021-04-20}, abstract = {Obscuration and confusion conspire to limit our knowledge of the inner Milky Way. Even at moderate distances, the identification of stellar systems becomes compounded by the extremely high density of background sources. Here we provide a very revealing example of these complications by unveiling a large, massive, young cluster in the Sagittarius arm that has escaped detection until now despite containing more than 30 stars brighter than \$G=13\$. By combining Gaia DR2 astrometry, Gaia and 2MASS photometry and optical spectroscopy, we find that the new cluster, which we name Valparaiso\textasciitilde 1, located at \$\textbackslash sim2.3\textbackslash :\$kpc, is about 75\textasciitilde Ma old and includes a large complement of evolved stars, among which we highlight the 4\textasciitilde d classical Cepheid CM\textasciitilde Sct and an M-type giant that probably represents the first detection of an AGB star in a Galactic young open cluster. Although strong differential reddening renders accurate parameter determination unfeasible with the current dataset, direct comparison to clusters of similar age suggests that Valparaiso\textasciitilde 1 was born as one of the most massive clusters in the Solar Neighbourhood, with an initial mass close to \$10\^\{4\}\textbackslash :\$M\$\_\{\textbackslash odot\}\$.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{negueruela_westerlund_2022, title = {Westerlund 1 under the Light of {{Gaia EDR3}}: {{Distance}}, Isolation, Extent, and a Hidden Population}, shorttitle = {Westerlund 1 under the Light of {{Gaia EDR3}}}, author = {Negueruela, Ignacio and Alfaro, Emilio J. and Dorda, Ricardo and Marco, Amparo and Apell{\'a}niz, Jes{\'u}s Ma{\'i}z and {Gonz{\'a}lez-Fern{\'a}ndez}, Carlos}, year = {2022}, month = apr, journal = {arXiv:2204.00422 [astro-ph]}, eprint = {2204.00422}, primaryclass = {astro-ph}, urldate = {2022-04-04}, abstract = {(Abridged) We have used Gaia EDR3 data, together with spectra of a large sample of luminous stars in the field surrounding Westerlund 1, to explore the extent of the cluster. We carry out a non-parametric analysis of proper motions and membership determination. We investigate the reddening and proper motions of several dozen OB stars and red supergiants {$<$} 1 deg away from Wd 1. We identify a population of kinematic members of Wd 1 that largely includes the known spectroscopic members. From their EDR3 parallaxes, we derive a distance to the cluster of \$4.23\^\{+0.23\}\_\{-0.21\}\$kpc. Extinction in this direction increases by a large amount around 2.8 kpc, due to dark clouds associated to the Scutum-Crux arm. As a consequence, we hardly see any stars at distances comparable to that of the cluster. The proper motions of Wd 1, however, are very similar to those of stars in the field surrounding it, but distinct. We find a second, astrometrically well-defined population in the foreground (\$d\textbackslash approx2\textbackslash :\$kpc), likely connected to the possible open cluster BH197. Wd 1 is very elongated, an effect not driven by the very heavy extinction to the East and South. We find a low-density halo extending up to 10' from the cluster centre, mainly in the NW quadrant. A few OB stars at larger distances from the cluster, most notably the LBV MN48, share its proper motions, suggesting that Wd 1 has little or no peculiar motion with respect to the field population of the Norma arm. However, we are unable to find any red supergiant that could belong to an extended population related to the cluster, although we observe several dozen such objects in the foreground. We find a substantial population of luminous OB members obscured by several more magnitudes of extinction than most known members. These objects, mostly located in the central region of the cluster, increase the population of OB supergiants by about 25\%.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{netopil_comparative_2015, title = {A Comparative Study on the Reliability of Open Cluster Parameters}, author = {Netopil, M. and Paunzen, E. and Carraro, G.}, year = {2015}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {582}, pages = {A19}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201526372}, urldate = {2019-09-19}, abstract = {\emph{Context. {$<$}i/{$>$}Open clusters are known as excellent tracers of the structure and chemical evolution of the Galactic disk, however, the accuracy and reliability of open cluster parameters is poorly known.\emph{Aims. {$<$}i/{$>$}In recent years, several studies aimed to present homogeneous open cluster parameter compilations, which are based on some different approaches and photometric data. These catalogues are excellent sources to facilitate testing of the actual accuracy of open cluster parameters.\emph{Methods. {$<$}i/{$>$}We compare seven cluster parameter compilations statistically and with an external sample, which comprises the mean results of individual studies. Furthermore, we selected the objects IC 4651, NGC 2158, NGC 2383, NGC 2489, NGC 2627, NGC 6603, and Trumpler 14, with the main aim to highlight differences in the fitting solutions. \emph{Results. {$<$}i/{$>$}We derived correction terms for each cluster parameter, using the external calibration sample. Most results by the compilations are reasonable scaled, but there are trends or constant offsets of different degree. We also identified one data set, which appears too erroneous to allow adjustments. After the correction, the mean intrinsic errors amount to about 0.2 dex for the age, 0.08 mag for the reddening, and 0.35 mag for the distance modulus. However, there is no study that characterises the cluster morphologies of all test cases in a correct and consistent manner. Furthermore, we found that the largest compilations probably include at least 20 percent of problematic objects, for which the parameters differ significantly. These could be among others doubtful or unlikely open clusters that do not facilitate an unambiguous fitting solution.}}}}}, copyright = {\textcopyright{} ESO, 2015}, langid = {english}}
@misc{nguyen_parsec_2022, title = {{{PARSEC V2}}.0: {{Stellar}} Tracks and Isochrones of Low and Intermediate Mass Stars with Rotation}, shorttitle = {{{PARSEC V2}}.0}, author = {Nguyen, C. T. and Costa, G. and Girardi, L. and Volpato, G. and Bressan, A. and Chen, Y. and Marigo, P. and Fu, X. and Goudfrooij, P.}, year = {2022}, month = jul, number = {arXiv:2207.08642}, eprint = {2207.08642}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2207.08642}, urldate = {2022-07-21}, abstract = {We present a new comprehensive collection of stellar evolutionary tracks and isochrones for rotating low- and intermediate-mass stars assembled with the updated version of PARSEC V2.0. This version includes our recent calibration of the extra mixing from overshooting and rotation, as well as several improvements in nuclear reaction network, treatment of convective zones, mass loss and other physical input parameters. The initial mass of the stellar models covers the range from 0.09 \$M\_\textbackslash odot\$ to 14 \$M\_\textbackslash odot\$, for six sets of initial metallicity, from Z=0.004 to Z=0.017. Rotation is considered for stars above \$\textbackslash sim 1 M\_\textbackslash odot\$ with a smooth transition between non rotating and extremely fast-rotating models, based on the initial mass. For stars more massive than \$\textbackslash sim 1.3\textasciitilde M\_\textbackslash odot\$ the full rotation range, from low to the critical one, is considered. We adopt the solar-scaled chemical mixture by Caffau et al. with Z\$\_\textbackslash odot\$ = 0.01524. All the evolutionary phases from the pre-main-sequence to the first few thermal-pulses on the asymptotic-giant-branch or central C exhaustion, are considered. The corresponding theoretical isochrones are further derived with TRILEGAL code and are converted in several photometric systems, taking into account different inclination angles. Besides magnitudes, they also offer many other stellar observables in line with the data that are being provided by current large surveys. The new collection is fully integrated in a user friendly WEB interface for the benefit of easily performing stellar population studies.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}}
@misc{noauthor_[1911.08390]_nodate, title = {[1911.08390] {{Bayesian Characterization}} of {{Main Sequence Binaries}} in the {{Old Open Cluster NGC}} 188}, urldate = {2019-11-20}, howpublished = {https://arxiv.org/abs/1911.08390}}
@misc{noauthor_200400018_nodate, title = {[2004.00018] {{Purveyors}} of Fine Halos. {{II}}. {{Chemodynamical}} Association of Halo Stars with {{Milky Way}} Globular Clusters}, urldate = {2020-04-02}, howpublished = {https://arxiv.org/abs/2004.00018}}
@misc{noauthor_220604567_nodate, title = {[2206.04567] {{New Coronae}} and {{Stellar Associations Revealed}} by a {{Clustering Analysis}} of the {{Solar Neighborhood}}}, urldate = {2022-06-15}, howpublished = {https://arxiv.org/abs/2206.04567}}
@misc{noauthor_formation_nodate, title = {The {{Formation}} of {{Stellar Clusters}} - {{NASA}}/{{ADS}}}, urldate = {2019-09-19}, abstract = {A powerful, streamlined new Astrophysics Data System}, howpublished = {https://ui.adsabs.harvard.edu/abs/2000prpl.conf..151C/abstract}, langid = {english}}
@misc{noauthor_graphics_nodate, title = {Graphics | {{Three}} New {{Galactic}} Star Clusters Discovered in the Field of the Open Cluster {{NGC}} 5999 with {{Gaia DR2}} - {{NASA}}/{{ADS}}}, urldate = {2019-11-21}, abstract = {A powerful, streamlined new Astrophysics Data System}, howpublished = {https://ui.adsabs.harvard.edu/abs/2019MNRAS.483.5508F/graphics}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SCIFN3HM\\graphics.html}}
@misc{noauthor_star_nodate, title = {Star {{Clusters Across Cosmic Time}} | {{Annual Review}} of {{Astronomy}} and {{Astrophysics}}}, urldate = {2019-10-25}, howpublished = {https://www.annualreviews.org/doi/full/10.1146/annurev-astro-091918-104430}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HPR2XXM2\\annurev-astro-091918-104430.html}}
@misc{noauthor_structure_nodate, title = {Structure and Mass Segregation in {{Galactic}} Stellar Clusters - {{NASA}}/{{ADS}}}, urldate = {2019-09-19}, abstract = {A powerful, streamlined new Astrophysics Data System}, howpublished = {https://ui.adsabs.harvard.edu/abs/2018MNRAS.473..849D/abstract}, langid = {english}}
@article{obasi_confirmation_2021, title = {Confirmation {{Of Two New Galactic Bulge Globular Clusters}}: {{FSR}} 19 and {{FSR}} 25}, shorttitle = {Confirmation {{Of Two New Galactic Bulge Globular Clusters}}}, author = {Obasi, Casmir and Gomez, Matias and Minniti, Dante and {Alonso-Garcia}, Javier}, year = {2021}, month = jun, journal = {arXiv:2106.09098 [astro-ph]}, eprint = {2106.09098}, primaryclass = {astro-ph}, urldate = {2021-07-21}, abstract = {Globular clusters (GCs) in the Milky Way (MW) bulge are very difficult to study because: i) they suffer from the severe crowding and galactic extinction; which are characteristic of these inner Galactic regions ii) they are more prone to be affected by dynamical processes. Therefore, they are relatively faint and difficult to map. However, deep near-infrared photometry like that provided by the VISTA Variables in the Via L\textbackslash 'actea Extended Survey (VVVX) is allowing us to map GCs in this crucial yet relatively uncharted region. Our results confirm with high confidence that both FSR 19 and FSR 25 are genuine MW bulge GCs. Each of the performed tests and resulting parameters provides clear evidence for the GC nature of these targets. We derive distances of 7.2\$\textbackslash pm\$0.7 kpc and D=7.0\$\textbackslash pm\$0.6 (corresponding to distance moduli of 14.29\$\textbackslash pm\$0.08 and 14.23\$\textbackslash pm\$0.07) for FSR 19 and FSR 25, respectively. Their ages and metallicities are 11 Gyr and [Fe/H]= -0.5 dex for both clusters, which were determined from Dartmouth and PARSEC isochrone fitting. The integrated luminosities are M\$\_\{Ks\}\$(FSR 19) = -7.72 mag and M\$\_\{Ks\}\$(FSR 25) = -7.31 mag which places them in the faint tail of the GC Luminosity Function. By adopting a King profile for their number distribution, we determine their core and tidal radii (\$r\_c\$, \$r\_t\$). For FSR 19, r\$\_\{c\}\$= 2.76\$\textbackslash pm\$0.36 pc and r\$\_\{t\}\$=5.31\$\textbackslash pm\$0.49 pc, while FSR 25 appears more extended with r\$\_\{c\}\$= 1.92\$\textbackslash pm\$0.59 pc and r\$\_\{t\}\$=6.85\$\textbackslash pm\$1.78 pc. Finally their mean GC PMs (from Gaia EDR3) are \$\textbackslash mu\_\{\textbackslash alpha\^\textbackslash ast\}\$= -2.50 \$\textbackslash pm\$0.76 mas \$yr\^\{-1\}\$, \$\textbackslash mu\_\{\textbackslash delta\}\$= -5.02 \$\textbackslash pm\$0.47 mas \$yr\^\{-1\}\$ and \$\textbackslash mu\_\{\textbackslash alpha\^\textbackslash ast\}\$= -2.61 \$\textbackslash pm\$ 1.27 mas \$yr\^\{-1\}\$ , \$\textbackslash mu\_\{\textbackslash delta\}\$= -5.23 \$\textbackslash pm\$0.74 mas \$yr\^\{-1\}\$ for FSR 19 and FSR 25, respectively. \vphantom\{\}}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\Z7HGVTZT\\2106.html}}
@article{oh_kinematic_modelling_2020, title = {Kinematic Modelling of Clusters with {{Gaia}}: The Death Throes of the {{Hyades}}}, author = {Oh, Semyeong and Evans, Neil Wyn}, year = {2020}, month = oct, volume = {498}, number = {2}, eprint = {2007.02969}, primaryclass = {astro-ph.SR}, pages = {1920--1938}, doi = {10.1093/mnras/staa2381}, archiveprefix = {arxiv}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,methods: data analysis,open clusters and associations: individual: Hyades,software: data analysis,stars: distances,stars: fundamental parameters}}
@misc{oliphant_guide_2006, title = {Guide to {{NumPy}}}, author = {Oliphant, Travis E.}, year = {2006}, urldate = {2020-06-24}, howpublished = {https://web.mit.edu/dvp/Public/numpybook.pdf}, file = {C\:\\Users\\Emily\\Zotero\\storage\\PT79UWVX\\numpybook.pdf}}
@article{olivares_kalkayotl_2020, title = {Kalkayotl: {{A}} Cluster Distance Inference Code}, shorttitle = {Kalkayotl}, author = {Olivares, J. and Sarro, L. M. and Bouy, H. and {Miret-Roig}, N. and Casamiquela, L. and Galli, P. A. B. and Berihuete, A. and Tarricq, Y.}, year = {2020}, month = dec, journal = {Astronomy \& Astrophysics}, volume = {644}, eprint = {2010.00272}, pages = {A7}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202037846}, urldate = {2021-01-05}, abstract = {Context: Stellar clusters are benchmarks for theories of star formation and evolution. The high precision parallax data of the Gaia mission allows significant improvements in the distance determination to stellar clusters and its stars. In order to have accurate and precise distance determinations, systematics like the parallax spatial correlations need to be accounted for, especially for stars in small sky regions. Aims: Provide the astrophysical community with a free and open code designed to simultaneously infer cluster parameters (i.e. distance and size) and the distances to its stars using Gaia parallax measurements. It includes cluster oriented prior families and is specifically designed to deal with the Gaia parallax spatial correlations. Methods: A Bayesian hierarchical model is created to allow the inference of both the cluster parameters and distances to its stars. Results: Using synthetic data that mimics Gaia parallax uncertainties and spatial correlations, we observe that our cluster oriented prior families result in distance estimates with smaller errors than those obtained with an exponentially decreasing space density prior. In addition, the treatment of the parallax spatial correlations minimizes errors in the estimated cluster size and stellar distances and avoids the underestimation of uncertainties. Although neglecting the parallax spatial correlations has no impact on the accuracy of cluster distance determinations, it underestimates the uncertainties and may result in measurements that are incompatible with the true value. Conclusions: The combination of prior knowledge with the treatment of Gaia parallax spatial correlations produces accurate (error {$<$}10\%) and trustworthy estimates (i.e. true values contained within the 2\$\textbackslash sigma\$ uncertainties) of clusters distances for clusters up to \textasciitilde 5 kpc, and cluster sizes for clusters up to \textasciitilde 1 kpc.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\MKMPNKKG\\2010.html}}
@article{pandey_interstellar_2003, title = {Interstellar Extinction in the Open Clusters towards Galactic Longitude around 130\textdegree}, author = {Pandey, A. K. and Upadhyay, K. and Nakada, Y. and Ogura, K.}, year = {2003}, month = jan, journal = {Astronomy \& Astrophysics}, volume = {397}, number = {1}, pages = {191--200}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361:20021509}, urldate = {2019-10-18}, abstract = {In this paper we present a detailed study of the intra-cluster reddening material in the young open clusters located around using colour-excess diagrams and two-colour diagrams. The study supports the universality of the extinction curves for , whereas for shorter wavelengths the curve depends upon the value of the \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} (total-to-selective absorption in the cluster region). The value of \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} in the case of NGC 654, NGC 869 and NGC 884 is found to be normal, whereas the value of \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} in the cluster regions NGC 1502 and IC 1805 indicates an anomalous reddening law in these regions. In the case of NGC 1502 the value of \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} is found to be lower whereas in the case of IC 1805 it is higher than the normal value of 3.1. Although the intra-cluster material indicates a higher value of \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} in the NGC 663 region, the error in the estimation of \emph{R{$<$}i/{$>$}\textsubscript{cluster{$<$}sub/{$>$} is too large to conclude anything. It is also found that the extinction process in the \emph{U{$<$}i/{$>$} band in the case of NGC 663 seems to be less efficient, whereas in the case of NGC 869 the process is more efficient.}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO, 2003}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GMQZQAZA\\aa2516.html}}
@article{pang_3d_2021, title = {{{3D Morphology}} of {{Open Clusters}} in the {{Solar Neighborhood}} with {{Gaia EDR}} 3: {{Its Relation}} to {{Cluster Dynamics}}}, shorttitle = {{{3D Morphology}} of {{Open Clusters}} in the {{Solar Neighborhood}} with {{Gaia EDR}} 3}, author = {Pang, Xiaoying and Li, Yuqian and Yu, Zeqiu and Tang, Shih-Yun and Dinnbier, Franti{\v s}ek and Kroupa, Pavel and Pasquato, Mario and Kouwenhoven, M. B. N.}, year = {2021}, month = may, journal = {The Astrophysical Journal}, volume = {912}, pages = {162}, issn = {0004-637X}, doi = {10.3847/1538-4357/abeaac}, urldate = {2022-03-24}, abstract = {We analyze the 3D morphology and kinematics of 13 open clusters (OCs) located within 500 pc of the Sun, using Gaia EDR 3 and kinematic data from the literature. Members of OCs are identified using the unsupervised machine-learning method StarGO, using five parameters (X, Y, Z, \$\{\textbackslash mu \}\_\{\textbackslash alpha \}\textbackslash cos \textbackslash delta ,\{\textbackslash mu \}\_\{\textbackslash delta \}\$ ). The OC sample covers an age range of 25 Myr to 2.65 Gyr. We correct the asymmetric distance distribution that is due to parallax error using Bayesian inversion. The uncertainty in the corrected distance for a cluster at 500 pc is 3.0-6.3 pc, depending on the intrinsic spatial distribution of its members. We determine the 3D morphology of the OCs in our sample and fit the spatial distribution of stars within the tidal radius in each cluster with an ellipsoid model. The shapes of the OCs are well described with oblate spheroids (NGC 2547, NGC 2516, NGC 2451A, NGC 2451B, and NGC 2232), prolate spheroids (IC 2602, IC 4665, NGC 2422, Blanco 1, and Coma Berenices), or triaxial ellipsoids (IC 2391, NGC 6633, and NGC 6774). The semimajor axis of the fitted ellipsoid is parallel to the Galactic plane for most clusters. Elongated filament-like substructures are detected in three young clusters (NGC 2232, NGC 2547, and NGC 2451B), while tidal-tail-like substructures (tidal tails) are found in older clusters (NGC 2516, NGC 6633, NGC 6774, Blanco 1, and Coma Berenices). Most clusters may be supervirial and expanding. N-body models of rapid gas expulsion with a star formation efficiency of {$\asymp$}1/3 are consistent with clusters more massive than 250 M{$\odot$}, while clusters less massive than 250 M{$\odot$} tend to agree with adiabatic gas expulsion models. Only five OCs (NGC 2422, NGC 6633, NGC 6774, Blanco 1, and Coma Berenices) show clear signs of mass segregation.}, keywords = {1160,1567,1596,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Open star clusters,Star clusters,Stellar dynamics}, annotation = {ADS Bibcode: 2021ApJ...912..162P}}
@article{pang_3d_2022, title = {{{3D Morphology}} of {{Open Clusters}} in the {{Solar Neighborhood}} with {{Gaia EDR3 II}}: {{Hierarchical Star Formation Revealed}} by {{Spatial}} and {{Kinematic Substructures}}}, shorttitle = {{{3D Morphology}} of {{Open Clusters}} in the {{Solar Neighborhood}} with {{Gaia EDR3 II}}}, author = {Pang, Xiaoying and Tang, Shih-Yun and Li, Yuqian and Yu, Zeqiu and Wang, Long and Li, Jiayu and Li, Yezhang and Wang, Yifan and Wang, Yanshu and Zhang, Teng and Pasquato, Mario and Kouwenhoven, M. B. N.}, year = {2022}, month = apr, journal = {arXiv:2204.06000 [astro-ph]}, eprint = {2204.06000}, primaryclass = {astro-ph}, urldate = {2022-04-19}, abstract = {We identify members of 65 open clusters in the solar neighborhood using the machine-learning algorithm StarGO based on Gaia EDR3 data. After adding members of twenty clusters from previous studies (Pang et al. 2021a,b; Li et al. 2021) we obtain 85 clusters, and study their morphology and kinematics. We classify the substructures outside the tidal radius into four categories: filamentary (f1) and fractal (f2) for clusters \${$<$}100\$ Myr, and halo (h) and tidal-tail (t) for clusters \${$>$}100\$ Myr. The kinematical substructures of f1-type clusters are elongated; these resemble the disrupted cluster Group X. Kinematic tails are distinct in t-type clusters, especially Pleiades. We identify 29 hierarchical groups in four young regions (Alessi 20, IC 348, LP 2373, LP 2442); ten among these are new. The hierarchical groups form filament networks. Two regions (Alessi 20, LP 2373) exhibit global "orthogonal" expansion (stellar motion perpendicular to the filament), which might cause complete dispersal. Infalling-like flows (stellar motion along the filament) are found in UBC 31 and related hierarchical groups in the IC 348 region. Stellar groups in the LP 2442 region (LP 2442 gp 1-5) are spatially well-mixed but kinematically coherent. A merging process might be ongoing in the LP 2442 subgroups. For younger systems (\$\textbackslash lesssim30\$ Myr), the mean axis ratio, cluster mass and half-mass radius tend to increase with age values. These correlations between structural parameters may imply two dynamical processes occurring in the hierarchical formation scenario in young stellar groups: (1) filament dissolution and (2) sub-group mergers.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{pang_disruption_2021, title = {Disruption of {{Hierarchical Clustering}} in the {{Vela OB2 Complex}} and the {{Cluster Pair Collinder}} 135 and {{UBC7}} with {{Gaia EDR3}}: {{Evidence}} of {{Supernova Quenching}}}, shorttitle = {Disruption of {{Hierarchical Clustering}} in the {{Vela OB2 Complex}} and the {{Cluster Pair Collinder}} 135 and {{UBC7}} with {{Gaia EDR3}}}, author = {Pang, Xiaoying and Yu, Zeqiu and Tang, Shih-Yun and Hong, Jongsuk and Yuan, Zhen and Pasquato, Mario and Kouwenhoven, M. B. N.}, year = {2021}, month = jun, journal = {arXiv:2106.07658 [astro-ph]}, eprint = {2106.07658}, primaryclass = {astro-ph}, urldate = {2021-06-16}, abstract = {We identify hierarchical structures in the Vela OB2 complex and the cluster pair Collinder 135 and UBC 7 with Gaia EDR3 using the neural network machine learning algorithm StarGO. Five second-level substructures are disentangled in Vela OB2, which are referred to as Huluwa 1 (Gamma Velorum), Huluwa 2, Huluwa 3, Huluwa 4 and Huluwa 5. Huluwa 1-5 may have originated through sequential star formation. The clusters Huluwa 1-3 are the older generation, with ages of 10-20 Myr, and generated stellar feedback that caused turbulence which fostered the formation of the younger-generation clusters, Huluwa 4-5 (10 Myr). The cluster pair Collinder 135 and UBC 7 was likely formed from the same molecular cloud, are coeval (40 Myr). The 3D morphology of Huluwa 1-5 resembles a shell-like structure, right along the rim of the Vela IRAS shell. A supernova explosion located inside the Vela IRAS shell quenched star formation in the younger generation Huluwa 4-5 and rapidly expelled the remaining gas from the clusters. This resulted in mass stratification across the shell, with more low-mass stars located along the inner rim of the shell, and more massive stars in the outer region of the shell. Mass segregation is observed only in the lowest-mass cluster Huluwa 5. Significant expansion is observed in Vela OB2 with a 1D expansion rate of \$(6.9-7.9)\textbackslash times10\^\{-2\}\$\textasciitilde km \$\textbackslash rm s\^\{-1\} pc\^\{-1\}\$. Expansion in the cluster pair is moderate. The velocity dispersions suggest that both Vela OB2 and the cluster pair are supervirial and are undergoing disruption. \$N\$-body simulations predict that Huluwa 1-5 in Vela OB2 and the cluster pair will continue to expand in the future 100 Myr and eventually dissolve.are supervirial and are undergoing disruption. \$N\$-body simulations predict that Huluwa 1-5 in Vela OB2 and the cluster pair will continue to expand in the future 100 Myr and eventually dissolve.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JAM8DA23\\2106.html}}
@article{pavanel_effects_2021, title = {The {{Effects}} of \$\textbackslash{{Lambda}}\${{CDM Dark Matter Substructure}} on the {{Orbital Evolution}} of {{Star Clusters}}}, author = {Pavanel, Nicholas and Webb, Jeremy J.}, year = {2021}, month = feb, journal = {arXiv:2102.06711 [astro-ph]}, eprint = {2102.06711}, primaryclass = {astro-ph}, urldate = {2021-02-24}, abstract = {We present a comprehensive study on how perturbations due to a distribution of \$\textbackslash Lambda\$CDM dark matter subhalos can lead to star clusters deviating from their orbits. Through a large suite of massless test particle simulations, we find that (1) subhalos with masses less than \$10\^8 M\_\{\textbackslash odot\}\$ negligibly affect test particle orbits, (2) perturbations lead to orbital deviations only in environments with substructure fractions \$f\_\{sub\} \textbackslash geq 1\textbackslash\%\$, (3) perturbations from denser subhalos produce larger orbital deviations, and (4) subhalo perturbations that are strong relative to the background tidal field lead to larger orbital deviations. To predict how the variation in test particle orbital energy \$\textbackslash sigma\_e(t)\$ increases with time, we test the applicability of theory derived from single-mass subhalo populations to populations where subhalos have a mass spectrum. We find \$\textbackslash sigma\_e(t)\$ can be predicted for test particle evolution within a mass spectrum of subhalos by assuming subhalos all have masses equal to the mean subhalo mass and by using the local mean subhalo separation to estimate the change in test particle velocities due to subhalo interactions. Furthermore, the orbital distance variation at an orbital distance \$r\$ can be calculated via \$\textbackslash sigma\_r=2.98 \textbackslash times 10\^\{-5\} \textbackslash pm 8 \textbackslash times 10\^\{-8\} (\textbackslash rm kpc\^\{-1\} km\^\{-2\} s\^\{2\}) \textbackslash times r \textbackslash times \textbackslash sigma\_e\$ with a dispersion about the line of best fit equalling 0.08 kpc. Finally, we conclude that clusters that orbit within 100 kpc of Milky Way-like galaxies experience a change no greater than \$2\textbackslash\%\$ in their dissolution times.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\L8GL9N5U\\2102.html}}
@article{pavani_characterization_2007, title = {Characterization of Open Cluster Remnants}, author = {Pavani, D. B. and Bica, E.}, year = {2007}, month = jun, journal = {Astronomy \& Astrophysics}, volume = {468}, number = {1}, pages = {139--150}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361:20066240}, urldate = {2019-11-18}, abstract = {\emph{Context.{$<$}i/{$>$}Despite progress in the theoretical knowledge of open cluster remnants and the growing search for observational identifications in recent years, open questions still remain. The methods used to analyze open cluster remnants and criteria to define them as physical systems are not homogeneous. In this work we present a systematic method for studying these objects that provides a view of their properties and allows their characterization.\emph{Aims.{$<$}i/{$>$}Eighteen remnant candidates are analyzed by means of photometric and proper motion data. These data provide information on objects and their fields. We establish criteria for characterizing open cluster remnants, taking observational uncertainties into account.\emph{Methods.{$<$}i/{$>$}2MASS J and H photometry is employed (i) to study structural properties of the objects by means of radial stellar density profiles, (ii) to test for any similarity between objects and fields with a statistical comparison method applied to the distributions of stars in the CMDs, and (iii) to obtain ages, reddening values, and distances from the CMD, taking an index of isochrone fit into account. The UCAC2 proper motions allowed an objective comparison between objects and large solid angle offset fields.\emph{Results.{$<$}i/{$>$}The objective analysis based on the present methods indicates 13 open-cluster remnants in the sample. Evidence of the presence of binary stars is found, as expected for dynamically evolved systems. Finally, we infer possible evolutionary stages among remnants from the structure, proper motion, and CMD distributions. The low stellar statistics for individual objects is overcome by means of the construction of composite proper motion and CMD diagrams. The distributions of remnants in the composite diagrams resemble the single-star and unresolved binary star distributions of open clusters.}}}}}, copyright = {\textcopyright{} ESO, 2007}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\W32X9FHR\\article.html}}
@article{pavlidou_substructure_2021, title = {Substructure in the {{Perseus Molecular Cloud}} Using {{Gaia DR2}}}, author = {Pavlidou, Tatiana and Scholz, Aleks and Teixeira, Paula S.}, year = {2021}, month = feb, journal = {arXiv:2102.08263 [astro-ph]}, eprint = {2102.08263}, primaryclass = {astro-ph}, urldate = {2021-02-24}, abstract = {We use photometric and kinematic data from Gaia DR2 to explore the structure of the star forming region associated with the molecular cloud of Perseus. Apart from the two well known clusters, IC 348 and NGC 1333, we present five new clustered groups of young stars, which contain between 30 and 300 members, named Autochthe, Alcaeus, Heleus, Electryon and Mestor. We demonstrate these are co-moving groups of young stars, based on how the candidate members are distributed in position, proper motion, parallax and colour-magnitude space. By comparing their colour-magnitude diagrams to isochrones we show that they have ages between 1 and 5 Myr. Using 2MASS and WISE colours we find that the fraction of stars with discs in each group ranges from 10 to 50 percent. The youngest of the new groups is also associated with a reservoir of cold dust, according to the Planck map at 353 GHz. We compare the ages and proper motions of the five new groups to those of IC 348 and NGC 1333. Autochthe is clearly linked with NGC 1333 and may have formed in the same star formation event. The seven groups separate roughly into two sets which share proper motion, parallax and age: Heleus, Electryon, Mestor as the older set, and NGC 1333, Autochthe as the younger set. Alcaeus is kinematically related to the younger set, but at a more advanced age, while the properties of IC 348 overlap with both sets. All older groups in this star forming region are located at higher galactic latitude.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HULJQIUS\\2102.html}}
@article{pavlik_primordial_2020, title = {Primordial Mass Segregation of Star Clusters with Primordial Binaries}, author = {Pavl{\'i}k, V{\'a}clav}, year = {2020}, month = apr, journal = {arXiv:2004.14389 [astro-ph]}, eprint = {2004.14389}, primaryclass = {astro-ph}, urldate = {2020-05-04}, abstract = {Observational results of young star-forming regions suggest that star clusters are completely mass segregated at birth. As a star cluster evolves dynamically, these initial conditions are gradually lost. For star clusters with single stars only and a canonical IMF, it has been suggested that traces of these initial conditions vanish at a time \$\textbackslash tau\_\textbackslash mathrm\{v\}\$ between \$3\$ and \$3.5\textbackslash,t\_\textbackslash mathrm\{rh\}\$ (initial half-mass relaxation times). Since a significant fraction of stars are observed in binary systems and it is widely accepted that most stars are born in binary systems we investigate what role a primordial binary population (even up to \$100\textbackslash,\textbackslash\%\$ binaries) plays in the loss of primordial mass segregation of young star clusters. We use numerical \$N\$-body models similar in size to the Orion Nebula Cluster (ONC) -- a representative of young open clusters -- integrated over several relaxation times to draw conclusions on the evolution of its mass segregation. We also compare our models to the observed ONC. We found that \$\textbackslash tau\_\textbackslash mathrm\{v\}\$ depends on the binary star fraction and the distribution of initial binary parameters that include semi-major axis, eccentricity and mass ratio. For instance, in the models with \$50\textbackslash,\textbackslash\%\$ binaries, we find \$\textbackslash tau\_\textbackslash mathrm\{v\} = (2.7 \textbackslash pm 0.8)\textbackslash,t\_\textbackslash mathrm\{rh\}\$, while for \$100\textbackslash,\textbackslash\%\$ binary fraction, we find a lower value, i.e. \$\textbackslash tau\_\textbackslash mathrm\{v\} = (2.1 \textbackslash pm 0.6)\textbackslash,t\_\textbackslash mathrm\{rh\}\$. We also conclude that the initially completely mass segregated clusters, even with binaries, are more compatible with the present-day ONC than the non-segregated ones.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\ZM28NWPM\\2004.html}}
@article{pedregosa_scikit-learn_2011, title = {Scikit-Learn: {{Machine Learning}} in {{Python}}}, shorttitle = {Scikit-Learn}, author = {Pedregosa, Fabian and Varoquaux, Ga{\"e}l and Gramfort, Alexandre and Michel, Vincent and Thirion, Bertrand and Grisel, Olivier and Blondel, Mathieu and Prettenhofer, Peter and Weiss, Ron and Dubourg, Vincent and Vanderplas, Jake and Passos, Alexandre and Cournapeau, David and Brucher, Matthieu and Perrot, Matthieu and Duchesnay, {\'E}douard}, year = {2011}, journal = {Journal of Machine Learning Research}, volume = {12}, number = {85}, pages = {2825--2830}, urldate = {2020-06-24}, abstract = {Scikit-learn is a Python module integrating a wide range of state-of-the-art machine learning algorithms for medium-scale supervised and unsupervised problems. This package focuses on bringing machine learning to non-specialists using a general-purpose high-level language. Emphasis is put on ease of use, performance, documentation, and API consistency. It has minimal dependencies and is distributed under the simplified BSD license, encouraging its use in both academic and commercial settings. Source code, binaries, and documentation can be downloaded from http://scikit-learn.sourceforge.net.}}
@article{penoyre_astrometric_2022, title = {Astrometric Identification of Nearby Binary Stars - {{I}}. {{Predicted}} Astrometric Signals}, author = {Penoyre, Zephyr and Belokurov, Vasily and Evans, N. Wyn}, year = {2022}, month = jun, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {513}, pages = {2437--2456}, issn = {0035-8711}, doi = {10.1093/mnras/stac959}, urldate = {2023-01-31}, abstract = {We examine the capacity to identify binary systems from astrometric errors and deviations alone. Until the release of the fourth Gaia data release, we lack the full astrometric time-series that the satellite records, but as we show can still infer the presence of binaries from the best-fitting models, and their error, already available. We generate a broad catalogue of simulated binary systems within 100 pc, and examine synthetic observations matching the Gaia survey's scanning law and astrometric data processing routine. We show how the unit weight error (UWE) and proper motion anomaly (PMA) vary as a function of period, and the properties of the binary. Both UWE and PMA peak for systems with a binary period close to the time baseline of the survey. Thus UWE can be expected to increase or remain roughly constant as we observe the same system over a longer baseline, and we suggest UWEeDR3 {$>$} 1.25 and {$\Delta$}UWE/UWEeDR3 {$>$} -0.25 as criteria to select astrometric binaries. For stellar binaries, we find detectable significant astrometric deviations for 80-90 per cent of our simulated systems in a period range from months to decades. We confirm that for systems with periods less than the survey's baseline the observed UWE scales {$\propto$} {$\varpi$} (parallax), a (semimajor axis), and \$\textbackslash Delta =\textbackslash frac\{|q-l|\}\{(1+q)(1+l)\}\$, where q and l are the mass and light ratio, respectively, with a modest dependence on viewing angle. For longer periods the signal is suppressed by a factor of roughly {$\propto$}P-2 (period). PMA is largest in orbits with slightly longer periods but obeys the same approximate scaling relationships.}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,binaries: general,parallaxes,proper motions}, annotation = {ADS Bibcode: 2022MNRAS.513.2437P}}
@article{penoyre_astrometric_2022-1, title = {Astrometric Identification of Nearby Binary Stars - {{II}}. {{Astrometric}} Binaries in the {{Gaia Catalogue}} of {{Nearby Stars}}}, author = {Penoyre, Zephyr and Belokurov, Vasily and Evans, N. Wyn}, year = {2022}, month = jul, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {513}, pages = {5270--5289}, issn = {0035-8711}, doi = {10.1093/mnras/stac1147}, urldate = {2023-01-31}, abstract = {We examine the capacity to identify binary systems from astrometric deviations alone. We apply our analysis to the Gaia eDR3 and DR2 data, specifically the Gaia Catalogue of Nearby Stars. We show we must renormalize (R)UWE over the local volume to avoid biasing local observations, giving a local unit weight error (LUWE). We use the simple criterion of LUWE{$>$}2, along with a handful of quality cuts to remove likely contaminants, to identify unresolved binary candidates. We identify 22 699 binary candidates within 100 pc of the Sun (just under 10 per cent of sources in this volume). We find an astrometric binary candidate fraction of around 20 per cent for giant stars, 10 per cent on the main sequence and lower than 1 per cent for white dwarfs. We also look for Variability Induced Movers, by computing the correlation between photometric variability and astrometric noise - and show that VIMs may dominate the binary population of sub-Solar mass MS stars. We discuss the possibility and limitations of identifying non-luminous massive companions from astrometry alone, but find that our method is insensitive to these. Finally, we compare the astrometric deviations of MS binaries to the simulated sample from paper I, which show excellent agreement, and compute the astrometric candidate binary fraction as a function of absolute magnitude.}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,binaries: general,parallaxes,proper motions}, annotation = {ADS Bibcode: 2022MNRAS.513.5270P}}
@article{penoyre_binary_2020, title = {Binary Deviations from Single Object Astrometry}, author = {Penoyre, Zephyr and Belokurov, Vasily and Wyn Evans, N. and Everall, A. and Koposov, S. E.}, year = {2020}, month = jun, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {495}, pages = {321--337}, issn = {0035-8711}, doi = {10.1093/mnras/staa1148}, urldate = {2023-01-31}, abstract = {Most binaries are undetected. Astrometric reductions of a system using the assumption that the object moves like a single point mass can be biased by unresolved binary stars. The discrepancy between the centre of mass of the system (which moves like a point mass) and the centre of light (which is what we observe) introduces additional motion. We explore the extent to which binary systems affect single object model fit to astrometric data. This tells us how observations are diluted by binaries and which systems cause the largest discrepancies - but it also allows us to make inferences about the binarity of populations based on observed astrometric error. By examining a sample of mock observations, we show that binaries with periods close to 1 yr can mimic parallax and thus bias distance measurements, while long-period binaries can introduce significant apparent proper motion. While these changes can soak up some of the error introduced by the binary, the total deviation from the best-fitting model can be translated into a lower limit on the on-sky separation of the pair. Throughout, we link these predictions to data from the Gaia satellite, while leaving the conclusions generalizable to other surveys.}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,binaries: general,methods: analytical,parallaxes,proper motions}, annotation = {ADS Bibcode: 2020MNRAS.495..321P}}
@article{perez_ipython_2007, title = {{{IPython}}: A {{System}} for {{Interactive Scientific Computing}}}, author = {P{\'e}rez, Fernando and Granger, Brian E.}, year = {2007}, month = may, journal = {Computing in Science and Engineering}, volume = {9}, number = {3}, pages = {21--29}, publisher = {{IEEE Computer Society}}, issn = {1521-9615}, doi = {10.1109/MCSE.2007.53}}
@article{perren_analysis_2022, title = {An Analysis of the Most Distant Catalogued Open Clusters -- {{Re-assessing}} Fundamental Parameters with {{Gaia EDR3}} and \$\textbackslash texttt\{\vphantom\}{{ASteCA}}\vphantom\{\}\$}, author = {Perren, G. I. and Pera, M. S. and Navone, H. D. and V{\'a}zquez, R. A.}, year = {2022}, month = apr, journal = {arXiv:2204.02153 [astro-ph]}, eprint = {2204.02153}, primaryclass = {astro-ph}, urldate = {2022-04-19}, abstract = {Several studies have been presented in the last few years applying some kind of automatic processing of data to estimate the fundamental parameters of open clusters. These parameters are later on employed in larger scale analyses, for example the structure of the Galaxy's spiral arms. The distance is one of the more straightforward parameters to estimate, yet enormous differences can still be found among published data. This is particularly true for open clusters located more than a few kpc away. We cross-matched several published catalogues and selected the twenty-five most distant open clusters (\${$>\$$}9000 pc). We then performed a detailed analysis of their fundamental parameters, with emphasis on their distances, to determine the agreement between catalogues and our estimates.\vphantom\{\} Photometric and astrometric data from the Gaia EDR3 survey was employed. The data was processed with our own membership analysis code (pyUPMASK), and our package for automatic fundamental cluster's parameters estimation (\$\textbackslash texttt\{ASteCA\}\$). We find differences in the estimated distances of up to several kpc between our results and those catalogued, even for the catalogues that show the best matches with \$\textbackslash texttt\{ASteCA\}\$ values. Large differences are also found for the age estimates. As a by-product of the analysis we find that vd Bergh-Hagen 176 could be the open cluster with the largest heliocentric distance catalogued to date. Caution is thus strongly recommended when using catalogued parameters of open clusters to infer large-scale properties of the Galaxy, particularly for those located more than a few kpc away.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{perren_sixteen_2020, title = {Sixteen Overlooked Open Clusters in the Fourth {{Galactic}} Quadrant. {{A}} Combined Analysis of {{UBVI}} Photometry and {{Gaia DR2}} with {{ASteCA}}}, author = {Perren, G. I. and Giorgi, E. E. and Moitinho, A. and Carraro, G. and Pera, M. S. and V{\'a}zquez, R. A.}, year = {2020}, month = mar, journal = {arXiv:2003.12138 [astro-ph]}, eprint = {2003.12138}, primaryclass = {astro-ph}, urldate = {2020-03-30}, abstract = {Aims: This paper has two main objectives: (1) To determine the intrinsic properties of 16 faint and mostly unstudied open clusters in the poorly known sector of the Galaxy at 270\$\^\textbackslash circ-\$300\$\^\textbackslash circ\$, to probe the Milky Way structure in future investigations. (2) To address previously reported systematics in Gaia DR2 parallaxes by comparing the cluster distances derived from photometry with those derived from parallaxes. Methods: Deep UBVI photometry of 16 open clusters was carried out. Observations were reduced and analyzed in an automaticway using the ASteCA package to get individual distances, reddening, masses, ages and metallicities. Photometric distances were compared to those obtained from a Bayesian analysis of Gaia DR2 parallaxes. Results: Ten out of the 16 clusters are true or highly probable open clusters. Two of them are quite young and follow the trace of the Carina Arm and the already detected warp. The rest of the clusters are placed in the interarm zone between the Perseus and Carina Arms as expected for older objects. We found that the cluster van den Berg-Hagen 85 is 7.5\$\textbackslash times\$10\$\^9\$ yrs old becoming then one of the oldest open cluster detected in our Galaxy so far. The relationship of these ten clusters with the Galaxy structure in the solar neighborhood is discussed. The comparison of distances from photometry and parallaxes data, in turn, reveals a variable level of disagreement. Conclusions: Various zero point corrections for Gaia DR2 parallax data recently reported were considered for a comparison between photometric and parallax based distances. The results tend to improve with some of these corrections. Photometric distance analysis suggest an average correction of \$\textbackslash sim\$+0.026 mas (to be added to the parallaxes). The correction may have a more intricate distance dependency, but addressing that level of detail will require a larger cluster sample.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\V7YDUSF8\\2003.html}}
@article{perryman_hipparcos_1997, title = {The {{HIPPARCOS Catalogue}}}, author = {Perryman, M. a. C. and Lindegren, L. and Kovalevsky, J. and Hoeg, E. and Bastian, U. and Bernacca, P. L. and Cr{\'e}z{\'e}, M. and Donati, F. and Grenon, M. and Grewing, M. and {van Leeuwen}, F. and {van der Marel}, H. and Mignard, F. and Murray, C. A. and Le Poole, R. S. and Schrijver, H. and Turon, C. and Arenou, F. and Froeschl{\'e}, M. and Petersen, C. S.}, year = {1997}, month = jul, journal = {Astronomy and Astrophysics, Vol. 323, p.L49-L52}, volume = {323}, pages = {L49}, issn = {0004-6361}, urldate = {2022-03-25}, abstract = {The principal observational characteristics of the Hipparcos Catalogue, and a summary of its main astrometric and photometric properties, are presented. Median astrometric standard errors (in position, parallax, and annual proper motion) are in the range 0.7-0.9 milliarcsec (mas) for stars brighter than 9 mag at the catalogue epoch (J1991.25). The catalogue is a materialisation of the ICRS reference system, coinciding with its principal axes at the level of +/-0.6mas, and with proper motions consistent with an inertial system at the level of +/-0.25mas/yr. The 118218 constituent stars provide a mean sky density of \textasciitilde 3 stars/deg\^2\^. The catalogue is available in printed and machine-readable forms.}, langid = {english}}
@misc{pflamm-altenburg_degree_2023, title = {On the Degree of Stochastic Asymmetry in the Tidal Tails of Star Clusters}, author = {{Pflamm-Altenburg}, J. and Kroupa, P. and Thies, I. and Jerabkova, T. and Beccari, G. and Prusti, T. and Boffin, H. M. J.}, year = {2023}, month = jan, number = {arXiv:2301.02251}, eprint = {2301.02251}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2301.02251}, urldate = {2023-01-13}, abstract = {Context: Tidal tails of star clusters are commonly understood to be populated symmetrically. Recently, the analysis of Gaia data revealed large asymmetries between the leading and trailing tidal tail arms of the four open star clusters Hyades, Praesepe, Coma Berenices and NGC 752. Aims: As the evaporation of stars from star clusters into the tidal tails is a stochastic process, the degree of stochastic asymmetry is quantified in this work. Methods: For each star cluster 1000 configurations of test particles are integrated in the combined potential of a Plummer sphere and the Galactic tidal field over the life time of the particular star cluster. For each of the four star clusters the distribution function of the stochastic asymmetry is determined and compared with the observed asymmetry. Results: The probabilities for a stochastic origin of the observed asymmetry of the four star clusters are: Praesepe \textasciitilde 1.7 sigma, Coma Berenices \textasciitilde 2.4 sigma, Hyades \textasciitilde 6.7 sigma, NGC 752 \textasciitilde 1.6 sigma. Conclusions: In the case of Praesepe, Coma Berenices and NGC 752 the observed asymmetry can be interpreted as a stochastic evaporation event. However, for the formation of the asymmetric tidal tails of the Hyades additional dynamical processes beyond a pure statistical evaporation effect are required.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{piatti_assessing_2023, title = {Assessing the Physical Reality of {{Milky Way}} Open Cluster Candidates}, author = {Piatti, A. E. and Illesca, D. M. F. and Massara, A. A. and Chiarpotti, M. and Rold{\'a}n, D. and Mor{\'o}n, M. and Bazzoni, F.}, year = {2023}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {518}, number = {4}, eprint = {2211.15483}, primaryclass = {astro-ph}, pages = {6216--6222}, doi = {10.48550/arXiv.2211.15483}, urldate = {2022-12-06}, abstract = {We report results on the analysis of eleven new Milky Way open cluster candidates, recently discovered from the detection of stellar overdensities in the Vector Point diagram, by employing extreme deconvolution Gaussian mixture models. We treated these objects as real open clusters and derived their fundamental properties with their associated intrinsic dispersions by exploring the parameter space through the minimization of likelihood functions on generated synthetic colour-magnitude diagrams (CMDs). The intrinsic dispersions of the resulting ages turned out to be much larger than those usually obtained for open clusters. Indeed, they resemble those of ages and metallicities of composite star field populations. We also traced their stellar number density profiles and mass functions, derived their total masses, Jacobi and tidal radii, which helped us as criteria while assessing their physical nature as real open clusters. Because the eleven candidates show a clear gathering of stars in the proper motion plane and some hint for similar distances, we concluded that they are possibly sparse groups of stars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@misc{piatti_catching_2023, title = {Catching a {{Milky Way}} Open Cluster in Its Last Breath}, author = {Piatti, Andr{\'e}s E.}, year = {2023}, month = jan, number = {arXiv:2301.04031}, eprint = {2301.04031}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2301.04031}, urldate = {2023-01-13}, abstract = {Theoretical models have suggested peculiar velocity dispersion profiles of star clusters facing dissolution. They predicted that, besides bound stars that still belong to the star cluster, and unbound ones already stripped off, there is an intermediate population of stars that having acquired the enough energy to escape the cluster are still within the cluster Jacobi radius. Both, potential escapers and unbound stars, show hot kinematics, not observed along tidal tails of star clusters. We report on the first evidence of an open cluster with stars crossing such a transitional scenario, namely: ASCC 92. The open cluster gathers nearly 10 percent of its initial total mass, and is moving toward Galactic regions affected by higher interstellar absorption. Precisely, the obscured appearance of the cluster could have hampered disentangling its true internal dynamical evolutionary stage, previously.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{piatti_elusive_2020, title = {The Elusive Tidal Tails of the {{Milky Way}} Globular Cluster {{NGC}} 7099}, author = {Piatti, A. E. and {Carballo-Bello}, J. A. and Mora, M. D. and Cenzano, C. and Navarrete, C. and Catelan, M.}, year = {2020}, month = sep, journal = {arXiv:2009.04290 [astro-ph]}, eprint = {2009.04290}, primaryclass = {astro-ph}, urldate = {2020-09-10}, abstract = {We present results on the extra-tidal features of the Milky Way globular cluster NGC 7099, using deep gr photometry obtained with the Dark Energy Camera (DECam). We reached nearly 6 mag below the cluster Main Sequence (MS) turnoff, so that we dealt with the most suitable candidates to trace any stellar structure located beyond the cluster tidal radius. From star-by-star reddening corrected color-magnitude diagrams (CMDs) we defined four adjacent strips along the MS, for which we built the respective stellar density maps, once the contamination by field stars was properly removed. The resulting field star cleaned stellar density maps show a short tidal tail and some scattered debris. Such extra-tidal features are hardly detected when much shallower Gaia DR2 data sets are used and the same CMD field star cleaning procedure is applied. Indeed, by using 2.5 magnitudes below the cluster MS turnoff as the faintest limit (G {$<$} 20.5 mag), cluster members turned out to be distributed within the cluster's tidal radius, and some hints for field star density variations are found across a circle of radius 3.5deg centered on the cluster and with similar CMD features as cluster stars. The proper motion distribution of these stars is distinguishable from that of the cluster, with some superposition, which resembles that of stars located beyond 3.5deg from the cluster center.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\G6FKAKT2\\2009.html}}
@article{piatti_extended_2019, title = {The Extended Main-Sequence Turn-off of the {{Milky Way}} Open Cluster {{Collinder}} 347}, author = {Piatti, Andr{\'e}s E. and Bonatto, Charles}, year = {2019}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {490}, pages = {2414--2420}, issn = {0035-8711}, doi = {10.1093/mnras/stz2798}, urldate = {2020-06-24}, abstract = {We made use of the Gaia DR2 archive to comprehensively study the Milky Way open cluster Collinder 347, known until now as a very young object of solar metal content. However, the G versus GBP - GRP colour-magnitude diagram (CMD) of bonafide probable cluster members, selected on the basis of individual stellar proper motions, their spatial distribution, and placement in the CMD, reveals the existence of a Hyades-like age open cluster (log(t /yr) = 8.8) of moderately metal-poor chemical content ([Fe/H] = -0.4 dex), with a present-day mass of 3.3 \texttimes{} 103 M{$\odot$}. The cluster exhibits an extended main-sequence turn-off (eMSTO) of nearly 500 Myr, while that computed assuming Gaussian distributions from photometric errors, stellar binarity, rotation, and metallicity spread yields an eMSTO of {$\sim$}340 Myr. Such an age difference points to the existence within the cluster of stellar populations with different ages.}, keywords = {open clusters and associations: general,techniques: photometric}}
@article{piatti_tidal_2020, title = {On the Tidal Tails of {{Milky Way}} Globular Clusters}, author = {Piatti, Andr{\'e}s E. and {Carballo-Bello}, Julio A.}, year = {2020}, month = apr, journal = {arXiv:2004.11747 [astro-ph]}, eprint = {2004.11747}, primaryclass = {astro-ph}, urldate = {2020-04-28}, abstract = {We report on the search for overall kinematical or structural conditions that have allowed some Milky Way globular clusters to presently develop tidal tails. For this purpose, we build a comprehensive catalogue of globular clusters with studies focused on their outermost regions and classified them in three categories: those with observed tidal tails, those with extra-tidal features different from tidal tails and those without any signature of extended stellar density profiles. When exploring different kinematical and structural parameter spaces, we found that globular clusters - irrespective from the presence of tidal tails, or any other kind of extra-tidal features or the absence of them - behave similarly. In general, globular clusters whose orbits are relatively more eccentric and very inclined respect to the Milky Way plane have undergone a larger amount of mass-loss by tidal disruption. The latter has also accelerated the internal dynamics toward a comparatively more advanced stage of evolution. These outcomes show that it is not straightforward to find any particular set of parameter space and dynamical conditions that can definitely predict tidal tails along globular clusters in the Milky Way.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\QCLHX7PZ\\2004.html}}
@article{piecka_aggregates_2021, title = {Aggregates of Clusters in the {{Gaia}} Data}, author = {Piecka, M. and Paunzen, E.}, year = {2021}, month = may, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2106.08920}, pages = {A54}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/202040139}, urldate = {2021-06-17}, abstract = {The precision of the parallax measurements by Gaia is unprecedented. As of Gaia Data Release 2, the number of known nearby open clusters has increased. Some of the clusters appear to be relatively close to each other and form aggregates, which makes them interesting objects to study. We study the aggregates of clusters which share several of the assigned member stars in relatively narrow volumes of the phase space. Using the most recent list of open clusters, we compare the cited central parallaxes with the histograms of parallax distributions of cluster aggregates. The aggregates were chosen based on the member stars which are shared by multiple clusters. Many of the clusters in the aggregates have been assigned parallaxes which coincide with the histograms. However, clusters that share a large number of members in a small volume of the phase space display parallax distributions which do not coincide with the values from the literature. This is the result of ignoring a possibility of assigning multiple probabilities to a single star. We propose that this small number of clusters should be analysed anew.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}}
@article{piskunov_global_2018, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{VI}}. {{Age}} Distribution and Cluster Formation History}, author = {Piskunov, A. E. and Just, A. and Kharchenko, N. V. and Berczik, P. and Scholz, R.-D. and Reffert, S. and Yen, S. X.}, year = {2018}, month = jun, journal = {Astronomy \& Astrophysics}, volume = {614}, pages = {A22}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201732337}, urldate = {2019-09-03}, abstract = {\emph{Context.{$<$}i/{$>$} The all-sky Milky Way Star Clusters (MWSC) survey provides uniform and precise ages, along with other relevant parameters, for a wide variety of clusters in the extended solar neighbourhood.\emph{Aims.{$<$}i/{$>$} In this study we aim to construct the cluster age distribution, investigate its spatial variations, and discuss constraints on cluster formation scenarios of the Galactic disk during the last 5 Gyrs.\emph{Methods.{$<$}i/{$>$} Due to the spatial extent of the MWSC, we have considered spatial variations of the age distribution along galactocentric radius \emph{R{$<$}i/{$>$}\textsubscript{\emph{G{$<$}i/{$><$}sub/{$>$}, and along \emph{Z{$<$}i/{$>$}-axis. For the analysis of the age distribution we used 2242 clusters, which all lie within roughly 2.5 kpc of the Sun. To connect the observed age distribution to the cluster formation history we built an analytical model based on simple assumptions on the cluster initial mass function and on the cluster mass-lifetime relation, fit it to the observations, and determined the parameters of the cluster formation law.\emph{Results.{$<$}i/{$>$} Comparison with the literature shows that earlier results strongly underestimated the number of evolved clusters with ages \emph{t{$<$}i/{$>$} {$\greaterequivlnt$} 100 Myr. Recent studies based on all-sky catalogues agree better with our data, but still lack the oldest clusters with ages \emph{t{$<$}i/{$>$} {$\greaterequivlnt$} 1 Gyr. We do not observe a strong variation in the age distribution along \emph{R{$<$}i/{$>$}\textsubscript{\emph{G{$<$}i/{$><$}sub/{$>$}, though we find an enhanced fraction of older clusters (\emph{t{$<$}i/{$>$} {$>$} 1 Gyr) in the inner disk. In contrast, the distribution strongly varies along \emph{Z{$<$}i/{$>$}. The high altitude distribution practically does not contain clusters with \emph{t{$<$}i/{$>$} {$<$} 1 Gyr. With simple assumptions on the cluster formation history, the cluster initial mass function and the cluster lifetime we can reproduce the observations. The cluster formation rate and the cluster lifetime are strongly degenerate, which does not allow us to disentangle different formation scenarios. In all cases the cluster formation rate is strongly declining with time, and the cluster initial mass function is very shallow at the high mass end.}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, keywords = {Catalogue: MWSC}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GFFED7N6\\Piskunov et al. - 2018 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\7D5M8WWX\\aa32337-17.html}}
@article{piskunov_tidal_2008, title = {Tidal Radii and Masses of Open Clusters}, author = {Piskunov, A. E. and Schilbach, E. and Kharchenko, N. V. and R{\"o}ser, S. and Scholz, R.-D.}, year = {2008}, month = jan, journal = {Astronomy and Astrophysics}, volume = {477}, pages = {165--172}, issn = {0004-6361}, doi = {10.1051/0004-6361:20078525}, urldate = {2020-02-12}, abstract = {Context: In a previous paper we obtained King's parameters for 236 of 650 Galactic open clusters identified in the ASCC-2.5. Aims: Estimating tidal radii by use of observable parameters available for all clusters. Bias-free results are required. Methods: We use methods of stellar statistics and develop a semi-empirical model of open clusters. Results: We check two effects impacting the determination of tidal radii from a fitting of King's profiles to the observed density distribution, i.e., ellipticity of open clusters and a bias depending on distances. Though a typical cluster has an elliptical form, the effect is rather weak to produce a prominent bias in the resulting tidal radii. In contrast, a distance dependent bias is not negligible and can cause a systematic underestimation of tidal radii computed with ASCC-2.5 data by a factor of two for the most distant clusters of our sample. This finding is used to correct the original results for 236 clusters and to extend the system of tidal radii and masses to all 650 clusters. We found that the semi-major axis of the projected distribution of cluster members on the sky is a parameter suited to estimate tidal radii of open clusters of our sample. No systematic differences are found between measured and calibrated tidal radii. From the comparison with mass estimates based on star counts and on the assumption of the Salpeter IMF, empirical evidence is obtained for an evolution of cluster mass functions starting in young clusters. Conclusions: The set of homogeneous parameters available for all clusters of our sample is extended by tidal radius and mass. Within 850 pc where our sample is complete, the distributions of tidal radii and masses peak at rt {$\approx$} 6 pc and log M\_c/m\_{$\odot$} {$\approx$} 2.5, respectively. In young open clusters, the mass distributions show differences to the Salpeter IMF, and this discrepancy increases with cluster age. The determined tidal radii and masses for 650 clusters are listed in a table that is available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/477/165}, keywords = {Galaxy: open clusters and associations: general,Galaxy: stellar content,solar neighborhood}}
@article{piskunov_towards_2007, title = {Towards Absolute Scales for the Radii and Masses of Open Clusters}, author = {Piskunov, A. E. and Schilbach, E. and Kharchenko, N. V. and R{\"o}ser, S. and Scholz, R.-D.}, year = {2007}, month = jun, journal = {Astronomy \& Astrophysics}, volume = {468}, number = {1}, pages = {151--161}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361:20077073}, urldate = {2019-11-21}, abstract = {\emph{Aims.{$<$}i/{$>$} In this paper we derive tidal radii and masses of open clusters in the nearest kiloparsecs around the Sun.\emph{Methods.{$<$}i/{$>$}For each cluster, the mass is estimated from tidal radii determined from a fitting of three-parameter King profiles to the observed integrated density distribution. Different samples of members are investigated.\emph{Results.{$<$}i/{$>$}For 236 open clusters, all contained in the catalogue ASCC-2.5, we obtain core and tidal radii, as well as tidal masses. The distributions of the core and tidal radii peak at about 1.5 pc and 7\textendash 10 pc, respectively. A typical relative error of the core radius lies between 15\% and 50\%, whereas, for the majority of clusters, the tidal radius was determined with a relative accuracy better than 20\%. Most of the clusters have tidal masses between 50 and 1000 , and for about half of the clusters, the masses were obtained with a relative error better than 50\%.}}}}, copyright = {\textcopyright{} ESO, 2007}, langid = {english}, keywords = {\_tablet}, file = {C\:\\Users\\Emily\\Zotero\\storage\\ATY95YBM\\article.html}}
@article{planckcollaboration_planck_2018_2020, title = {Planck 2018 Results. {{VI}}. {{Cosmological}} Parameters}, author = {{Planck Collaboration} and Aghanim, N. and Akrami, Y. and Ashdown, M. and Aumont, J. and Baccigalupi, C. and Ballardini, M. and Banday, A. J. and Barreiro, R. B. and Bartolo, N. and Basak, S. and Battye, R. and Benabed, K. and Bernard, J. -P. and Bersanelli, M. and Bielewicz, P. and Bock, J. J. and Bond, J. R. and Borrill, J. and Bouchet, F. R. and Boulanger, F. and Bucher, M. and Burigana, C. and Butler, R. C. and Calabrese, E. and Cardoso, J. -F. and Carron, J. and Challinor, A. and Chiang, H. C. and Chluba, J. and Colombo, L. P. L. and Combet, C. and Contreras, D. and Crill, B. P. and Cuttaia, F. and {de Bernardis}, P. and {de Zotti}, G. and Delabrouille, J. and Delouis, J. -M. and Di Valentino, E. and Diego, J. M. and Dor{\'e}, O. and Douspis, M. and Ducout, A. and Dupac, X. and Dusini, S. and Efstathiou, G. and Elsner, F. and En{\ss}lin, T. A. and Eriksen, H. K. and Fantaye, Y. and Farhang, M. and Fergusson, J. and {Fernandez-Cobos}, R. and Finelli, F. and Forastieri, F. and Frailis, M. and Fraisse, A. A. and Franceschi, E. and Frolov, A. and Galeotta, S. and Galli, S. and Ganga, K. and {G{\'e}nova-Santos}, R. T. and Gerbino, M. and Ghosh, T. and {Gonz{\'a}lez-Nuevo}, J. and G{\'o}rski, K. M. and Gratton, S. and Gruppuso, A. and Gudmundsson, J. E. and Hamann, J. and Handley, W. and Hansen, F. K. and Herranz, D. and Hildebrandt, S. R. and Hivon, E. and Huang, Z. and Jaffe, A. H. and Jones, W. C. and Karakci, A. and Keih{\"a}nen, E. and Keskitalo, R. and Kiiveri, K. and Kim, J. and Kisner, T. S. and Knox, L. and Krachmalnicoff, N. and Kunz, M. and {Kurki-Suonio}, H. and Lagache, G. and Lamarre, J. -M. and Lasenby, A. and Lattanzi, M. and Lawrence, C. R. and Le Jeune, M. and Lemos, P. and Lesgourgues, J. and Levrier, F. and Lewis, A. and Liguori, M. and Lilje, P. B. and Lilley, M. and Lindholm, V. and {L{\'o}pez-Caniego}, M. and Lubin, P. M. and Ma, Y. -Z. and {Mac{\'i}as-P{\'e}rez}, J. F. and Maggio, G. and Maino, D. and Mandolesi, N. and Mangilli, A. and {Marcos-Caballero}, A. and Maris, M. and Martin, P. G. and Martinelli, M. and {Mart{\'i}nez-Gonz{\'a}lez}, E. and Matarrese, S. and Mauri, N. and McEwen, J. D. and Meinhold, P. R. and Melchiorri, A. and Mennella, A. and Migliaccio, M. and Millea, M. and Mitra, S. and {Miville-Desch{\^e}nes}, M. -A. and Molinari, D. and Montier, L. and Morgante, G. and Moss, A. and Natoli, P. and {N{\o}rgaard-Nielsen}, H. U. and Pagano, L. and Paoletti, D. and Partridge, B. and Patanchon, G. and Peiris, H. V. and Perrotta, F. and Pettorino, V. and Piacentini, F. and Polastri, L. and Polenta, G. and Puget, J. -L. and Rachen, J. P. and Reinecke, M. and Remazeilles, M. and Renzi, A. and Rocha, G. and Rosset, C. and Roudier, G. and {Rubi{\~n}o-Mart{\'i}n}, J. A. and {Ruiz-Granados}, B. and Salvati, L. and Sandri, M. and Savelainen, M. and Scott, D. and Shellard, E. P. S. and Sirignano, C. and Sirri, G. and Spencer, L. D. and Sunyaev, R. and {Suur-Uski}, A. -S. and Tauber, J. A. and Tavagnacco, D. and Tenti, M. and Toffolatti, L. and Tomasi, M. and Trombetti, T. and Valenziano, L. and Valiviita, J. and Van Tent, B. and Vibert, L. and Vielva, P. and Villa, F. and Vittorio, N. and Wandelt, B. D. and Wehus, I. K. and White, M. and White, S. D. M. and Zacchei, A. and Zonca, A.}, year = {2020}, month = sep, volume = {641}, eprint = {1807.06209}, primaryclass = {astro-ph.CO}, pages = {A6}, doi = {10.1051/0004-6361/201833910}, archiveprefix = {arxiv}, keywords = {Astrophysics - Cosmology and Nongalactic Astrophysics,cosmic background radiation,cosmological parameters}}
@article{platais_search_1998, title = {A {{Search}} for {{Star Clusters}} from the {{HIPPARCOS Data}}}, author = {Platais, Imants and {Kozhurina-Platais}, Vera and {van Leeuwen}, Floor}, year = {1998}, month = nov, journal = {The Astronomical Journal}, volume = {116}, pages = {2423--2430}, issn = {0004-6256}, doi = {10.1086/300606}, urldate = {2021-11-29}, abstract = {We present results of a search for nearby star clusters and associations using Hipparcos Catalogue data, restricting the sample to stars with parallaxes above 2 mas (d {$<\sptilde$} 500 pc). Two new OB associations have been identified in the Carina-Vela and Cepheus-Cygnus-Lyra-Vulpecula regions. A very probable new open cluster has been discovered in Carina. The cluster, a Car, named after its brightest member, is young (60 Myr) and nearby (d = 132 pc). However, only seven bona fide members can be drawn from the Hipparcos data. We report a detection of nine open cluster candidates in the distance range of 150 to 400 pc, and six possible associations almost all located within the Gould belt, although slightly older than the known nearby associations. In all cases, we present Yale theoretical isochrone fits to the color-magnitude diagrams, which indicate a moderate spread of ages between 60 to 200 Myr. Evidently, these young open cluster and association candidates are related to the overall distribution of young OB and A-type stars in the solar neighborhood.}, keywords = {CATALOGS,GALAXY: OPEN CLUSTERS AND ASSOCIATIONS: GENERAL}, annotation = {ADS Bibcode: 1998AJ....116.2423P}}
@article{plummer_problem_1911, title = {On the Problem of Distribution in Globular Star Clusters}, author = {Plummer, H. C.}, year = {1911}, month = mar, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {71}, pages = {460--470}, issn = {0035-8711}, doi = {10.1093/mnras/71.5.460}, urldate = {2022-07-25}, annotation = {ADS Bibcode: 1911MNRAS..71..460P}}
@article{poovelil_open_2020, title = {Open {{Cluster Chemical Homogeneity Throughout}} the {{Milky Way}}}, author = {Poovelil, Vijith Jacob and Zasowski, G. and Hasselquist, S. and Seth, A. and Donor, John and Beaton, Rachael L. and Cunha, K. and Frinchaboy, Peter M. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Hawkins, K. and Kratter, K. M. and Lane, Richard R. and Nitschelm, C.}, year = {2020}, month = sep, journal = {arXiv:2009.06777 [astro-ph]}, eprint = {2009.06777}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {The chemical homogeneity of surviving stellar clusters contains important clues about interstellar medium (ISM) mixing efficiency, star formation, and the enrichment history of the Galaxy. Existing measurements in a handful of open clusters suggest homogeneity in several elements at the 0.03 dex level. Here we present (i) a new cluster member catalog based only on APOGEE radial velocities and Gaia-DR2 proper motions, (ii) improved abundance uncertainties for APOGEE cluster members, and (iii) the dependence of cluster homogeneity on Galactic and cluster properties, using abundances of eight elements from the APOGEE survey for ten high-quality clusters. We find that cluster homogeneity is uncorrelated with Galactocentric distance, |Z|, age, and metallicity. However, velocity dispersion, which is a proxy for cluster mass, is positively correlated with intrinsic scatter at relatively high levels of significance for [Ca/Fe] and [Mg/Fe]. We also see a possible positive correlation at a low level of significance for [Ni/Fe], [Si/Fe], [Al/Fe], and [Fe/H], while [Cr/Fe] and [Mn/Fe] are uncorrelated. The elements that show a correlation with velocity dispersion are those that are predominantly produced by core-collapse supernovae (CCSNe). However, the small sample size and relatively low correlation significance highlight the need for follow-up studies. If borne out by future studies, these findings would suggest a quantitative difference between the correlation lengths of elements produced predominantly by Type\textasciitilde Ia SNe versus CCSNe, which would have implications for Galactic chemical evolution models and the feasibility of chemical tagging.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\7VSZQTC7\\2009.html}}
@article{portegies_zwart_young_2010, title = {Young {{Massive Star Clusters}}}, author = {Portegies Zwart, Simon F. and McMillan, Stephen L. W. and Gieles, Mark}, year = {2010}, month = sep, journal = {Annual Review of Astronomy and Astrophysics}, volume = {48}, pages = {431--493}, issn = {0066-4146}, doi = {10.1146/annurev-astro-081309-130834}, urldate = {2022-01-27}, abstract = {Young massive clusters (YMCs) are dense aggregates of young stars that form the fundamental building blocks of galaxies. Several examples exist in the Milky Way Galaxy and the Local Group, but they are particularly abundant in starburst and interacting galaxies. The few YMCs that are close enough to resolve are of prime interest for studying the stellar mass function and the ecological interplay between stellar evolution and stellar dynamics. The distant unresolved clusters may be effectively used to study the star-cluster mass function, and they provide excellent constraints on the formation mechanisms of young cluster populations. YMCs are expected to be the nurseries for many unusual objects, including a wide range of exotic stars and binaries. So far only a few such objects have been found in YMCs, although their older cousins, the globular clusters, are unusually rich in stellar exotica. In this review, we focus on star clusters younger than {$\sim$}100 Myr, more than a few current crossing times old, and more massive than {$\sim$}10\textsuperscript{4}M\textsubscript{{$\odot$}}; the size of the cluster and its environment are considered less relevant as distinguishing parameters. We describe the global properties of the currently known young massive star clusters in the Local Group and beyond, and discuss the state of the art in observations and dynamical modeling of these systems. In order to make this review readable by observers, theorists, and computational astrophysicists, we also review the cross-disciplinary terminology.}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CKNP2Z5V\\abstract.html}}
@article{possel_beginners_2020, title = {A {{Beginner}}'s {{Guide}} to {{Working}} with {{Astronomical Data}}}, author = {P{\"o}ssel, Markus}, year = {2020}, month = jan, journal = {arXiv:1905.13189 [astro-ph, physics:physics]}, eprint = {1905.13189}, primaryclass = {astro-ph, physics:physics}, urldate = {2020-01-08}, abstract = {This elementary review covers the basics of working with astronomical data, notably with images, spectra and higher-level (catalog) data. The basic concepts and tools are presented using both application software (DS9 and TOPCAT) and Python. The level of presentation is suitable for undergraduate students, but should also be accessible to advanced high school students.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Physics - Physics Education}}
@article{prescod-weinstein_reframing_2020, title = {Reframing Astronomical Research through an Anticolonial Lens -- for {{TMT}} and Beyond}, author = {{Prescod-Weinstein}, Chanda and Walkowicz, Lucianne M. and Tuttle, Sarah and Nord, Brian and Neilson, Hilding R.}, year = {2020}, month = jan, journal = {arXiv:2001.00674 [astro-ph]}, eprint = {2001.00674}, primaryclass = {astro-ph}, urldate = {2020-01-07}, abstract = {This white paper explains that professional astronomy has benefited from settler colonial white supremacist patriarchy. We explicate the impact that this has had on communities which are not the beneficiaries of colonialism and white supremacy. We advocate for astronomers to reject these benefits in the future, and we make proposals regarding the steps involved in rejecting colonialist white supremacy's benefits. We center ten recommendations on the timely issue of what to do about the Thirty Meter Telescope (TMT) on Maunakea in Hawaii. This paper is written in solidarity with and support of efforts by Native Hawaiian scientists (e.g. Kahanamoku et al. 2019).}, archiveprefix = {arxiv}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\LTBUR2TL\\2001.html}}
@article{price-jones_strong_2020, title = {Strong Chemical Tagging with {{APOGEE}}: 21 Candidate Star Clusters That Have Dissolved across the {{Milky Way}} Disc}, shorttitle = {Strong Chemical Tagging with {{APOGEE}}}, author = {{Price-Jones}, Natalie and Webb, Jeremy J. and Prieto, Carlos Allende and Beaton, Rachael and Brownstein, Joel R. and Cohen, Roger E. and Cunha, Katia and Donor, John and Frinchaboy, Peter M. and {Garc{\'i}a-Hern{\'a}ndez}, D. A. and Lane, Richard R. and Majewski, Steven R. and Nidever, David L. and {Roman-Lopes}, Alexandre and Bovy, Jo}, year = {2020}, month = apr, journal = {arXiv:2004.04263 [astro-ph]}, eprint = {2004.04263}, primaryclass = {astro-ph}, urldate = {2020-04-14}, abstract = {Chemically tagging groups of stars born in the same birth cluster is a major goal of spectroscopic surveys. To investigate the feasibility of such strong chemical tagging, we perform a blind chemical tagging experiment on abundances measured from APOGEE survey spectra. We apply a density-based clustering algorithm to the eight dimensional chemical space defined by [Mg/Fe], [Al/Fe], [Si/Fe], [K/Fe], [Ti/Fe], [Mn/Fe], [Fe/H], and [Ni/Fe], abundances ratios which together span multiple nucleosynthetic channels. In a high quality sample of 182,538 giant stars, we detect twenty-one candidate clusters with more than fifteen members. Our candidate clusters are more chemically homogeneous than a population of non-member stars with similar [Mg/Fe] and [Fe/H], even in abundances not used for tagging. Group members are consistent with having the same age and fall along a single stellar-population track in logg vs. Teff space. Each group's members are distributed over multiple kpc, and the spread in their radial and azimuthal actions increases with age. We qualitatively reproduce this increase using N-body simulations of cluster dissolution in Galactic potentials that include transient winding spiral arms. Observing our candidate birth clusters with high-resolution spectroscopy in other wavebands to investigate their chemical homogeneity in other nucleosynthetic groups will be essential to confirming the efficacy of strong chemical tagging. Our initially spatially-compact but now widely dispersed candidate clusters will provide novel limits on chemical evolution and orbital diffusion in the Galactic disc, and constraints on star formation in loosely-bound groups.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\FTLURK3I\\2004.html}}
@article{price-whelan_discovery_2019, title = {Discovery of a Disrupting Open Cluster Far into the {{Milky Way}} Halo: A Recent Star Formation Event in the Leading Arm of the {{Magellanic}} Stream?}, shorttitle = {Discovery of a Disrupting Open Cluster Far into the {{Milky Way}} Halo}, author = {{Price-Whelan}, Adrian M. and Nidever, David L. and Choi, Yumi and Schlafly, Edward F. and Morton, Timothy and Koposov, Sergey E. and Belokurov, Vasily}, year = {2019}, month = dec, journal = {The Astrophysical Journal}, volume = {887}, number = {1}, eprint = {1811.05991}, pages = {19}, issn = {1538-4357}, doi = {10.3847/1538-4357/ab4bdd}, urldate = {2020-02-06}, abstract = {We report the discovery of a young ({$\tau$} {$\sim$} 117 Myr), low-mass (M {$\sim$} 1200 M ), metal-poor ([Fe/H] {$\sim$} -1.14) stellar association at a heliocentric distance D {$\approx$} 28.7 kpc, placing it far into the Milky Way halo. At its present Galactocentric position (R, z) {$\sim$} (23, 15) kpc, the association is (on the sky) near the leading arm of the gas stream emanating from the Magellanic cloud system, but is located {$\approx$} 60{$\smwhtcircle$} from the Large Magellanic Cloud (LMC) center on the other side of the Milky Way (MW) disk. If the cluster is co-located with HI gas in the stream, we directly measure the distance to the leading arm of the Magellanic stream. The measured distance is inconsistent with Magellanic stream model predictions that do not account for ram pressure and gas interaction with the MW disk. The estimated age of the cluster is consistent with the time of last passage of the leading arm gas through the Galactic midplane; We therefore speculate that this star-formation event was triggered by its last disk midplane passage. Most details of this idea remain a puzzle: the Magellanic stream has low column density, the MW disk at large radii has low gas density, and the relative velocity of the leading arm and MW gas is large. However it formed, the discovery of a young stellar cluster in the MW halo presents an interesting opportunity for study. This cluster was discovered with Gaia astrometry and photometry alone, but follow-up DECam photometry was crucial for measuring its properties.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\2GIYYWFL\\Price-Whelan et al_2019_Discovery of a disrupting open cluster far into the Milky Way halo.pdf;C\:\\Users\\Emily\\Zotero\\storage\\GE9WGVR3\\Price-Whelan et al_2019_Discovery of a disrupting open cluster far into the Milky Way halo.pdf}}
@article{prisegen_white_2020, title = {White Dwarf-Open Cluster Associations Based on {{Gaia DR2}}}, author = {Pri{\v s}egen, M. and Piecka, M. and Faltov{\'a}, N. and Kajan, M. and Paunzen, E.}, year = {2020}, month = nov, journal = {arXiv:2011.03578 [astro-ph]}, eprint = {2011.03578}, primaryclass = {astro-ph}, urldate = {2020-11-30}, abstract = {Fundamental parameters and physical processes leading to the formation of white dwarfs (WDs) may be constrained and refined by discovering WDs in open clusters (OCs). Cluster membership can be utilized to establish the precise distances, luminosities, ages, and progenitor masses of such WDs. We compile a list of probable WDs that are OC members in order to facilitate WD studies that are impractical or difficult to conduct for Galactic field WDs. We use recent catalogs of WDs and OCs that are based on the second data release of the \textbackslash textit\{Gaia\} satellite mission (GDR2) to identify WDs that are OC members. This crossmatch is facilitated by the astrometric and photometric data contained in GDR2 and the derived catalogs. Assuming that most of the WD members are of the DA type, we estimate the WD masses, cooling ages, and progenitor masses. We have detected several new likely WD members and reassessed the membership of the literature WDs that had been previously associated with the studied OCs. Several of the recovered WDs fall into the recently reported discontinuity in the initial-final mass relation (IFMR) around \$M\_\{i\} \textbackslash sim 2.0 M\_\{\textbackslash odot\}\$, which allows for tighter constrains on the IFMR in this regime.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HYPN6FW8\\2011.html}}
@article{qin_discovery_2021, title = {Discovery of {{Four New Clusters}} in the {{Cygnus Cloud}}}, author = {Qin, Song-mei and Li, Jing and Chen, Li and Zhong, Jing}, year = {2021}, journal = {Research in Astronomy and Astrophysics}, volume = {21}, number = {2}, eprint = {2008.07164}, pages = {045}, urldate = {2020-08-21}, abstract = {We report the discovery of four new open clusters (named as QC 1, QC 2, QC3 and QC 4) in the direction of Cygnus Cloud and select their members based on five astrometric parameters (l, b, \textbackslash varpi, \textbackslash mu\^*\_\{\textbackslash alpha\}, \textbackslash mu\_\{\textbackslash delta\}) of Gaia DR2. We also derive their astrophysical parameters for each new cluster. Structure parameters are generated by fitting the radial density distribution with King's profile. Using solar metallicity, we performed isochrone-fitting on their purified color-magnitude diagrams (CMDs) to achieve the age of the clusters. The known cluster NGC 7062 at adjacent area is chosen to verify our identification process. The estimated distance, reddening and age of NGC 7062 are in good agreement with the literature.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\CCIMNXDP\\2008.html}}
@article{qin_hunting_2023, title = {Hunting for {{Neighboring Open Clusters}} with {{Gaia DR3}}: 101 {{New Open Clusters}} within 500 Pc}, shorttitle = {Hunting for {{Neighboring Open Clusters}} with {{Gaia DR3}}}, author = {Qin, Songmei and Zhong, Jing and Tang, Tong and Chen, Li}, year = {2023}, journal = {The Astrophysical Journal Supplement Series}, volume = {265}, number = {1}, eprint = {2212.11034}, primaryclass = {astro-ph}, pages = {12}, doi = {10.48550/arXiv.2212.11034}, urldate = {2023-01-13}, abstract = {We systematically searched for open clusters in the solar neighborhood within 500 pc using pyUPMASK and HDBSCAN clustering algorithms based on \{\textbackslash it Gaia\} DR3. Taking into consideration that the physical size for most open clusters is less than 50 pc, we adopted a slicing approach for different distance shells and identified 324 neighboring open clusters, including 223 reported open clusters and 101 newly discovered open clusters (named as OCSN, Open Cluster of Solar Neighborhood). Our discovery has increased the number of open clusters in the solar neighborhood by about 45\textbackslash\%. In this work, larger spatial extents and more member stars were attained for our cluster sample. We provided the member stars and the membership probabilities through the pyUPMASK algorithm for each cluster and derived their astrophysical, age, and structural parameters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}}
@article{rain_blue_2020, title = {The Blue Straggler Population of the Open Clusters {{Trumpler}} 5, {{Trumpler}} 20, and {{NGC}} 2477}, author = {Rain, M. J. and Carraro, G. and Ahumada, J. and Villanova, S. and Boffin, H. and Monaco, L.}, year = {2020}, month = oct, journal = {arXiv:2010.06884 [astro-ph]}, eprint = {2010.06884}, primaryclass = {astro-ph}, urldate = {2020-10-15}, abstract = {We present a study, based on Gaia DR2, of the population of blue straggler stars (BSS) in the open clusters Trumpler 5, Trumpler 20, and NGC 2477. All candidates were selected according to their position in the color-magnitude diagram, to their proper motion components, and to their parallax. We also looked for yellow stragglers, i.e., possible evolved blue stragglers. We found that Trumpler 5 hosts a large BSS population, which allowed us to analyze their radial distribution as a probe of the cluster's dynamical status. The BSS distribution was compared with that of red giant branch stars (RGB) to evaluate mass segregation. Our results indicate that blue straggler stars are not more centrally concentrated than RGB stars in any of the clusters. The radial distribution of BSS in Trumpler 5 is flat. Additionally, using a multi-epoch radial velocity survey conducted with the high-resolution spectrograph FLAMES/GIRAFFE at VLT, we measured the radial velocities of a sample of stragglers, for the sake of comparison with the mean radial velocity and the velocity dispersion of the clusters. Based on the radial velocity variations for different epochs, we roughly classified these stars as possible close-or long-period binaries.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HSQAWSV9\\2010.html}}
@article{ramirez_vvv_2021, title = {The {{VVV Open Cluster Project}}. {{Near-infrared}} Sequences of {{NGC6067}}, {{NGC6259}}, {{NGC4815}}, {{Pismis18}}, {{Trumpler23}}, and {{Trumpler20}}}, author = {Ram{\'i}rez, K. Pe{\~n}a and {Gonz{\'a}lez-Fern{\'a}ndez}, C. and Chen{\'e}, A.-N. and Alegr{\'i}a, S. Ram{\'i}rez}, year = {2021}, journal = {Monthly Notices of the Royal Astronomical Society}, eprint = {2102.04303}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stab328}, urldate = {2021-02-09}, abstract = {Open clusters are central elements of our understanding of the Galactic disk evolution, as an accurate determination of their parameters leads to an unbiased picture of our Galaxy's structure. Extending the analysis towards fainter magnitudes in cluster sequences has a significant impact on the derived fundamental parameters, such as extinction and total mass. We perform a homogeneous analysis of six open stellar clusters in the Galactic disk using kinematic and photometric information from the Gaia DR2 and VVV surveys: NGC6067, NGC6259, NGC4815, Pismis18, Trumpler23, and Trumpler20. We implement two coarse-to-fine characterization methods: first, we employ Gaussian mixture models to tag fields around each open cluster in the proper motion space, and then we apply an unsupervised machine learning method to make the membership assignment to each cluster. For the studied clusters, with ages in the \$\textbackslash sim\$120-1900 Myr range, we report an increase of \$\textbackslash sim\$45 \% new member candidates on average in our sample. The data-driven selection approach of cluster members makes our catalog a valuable resource for testing stellar evolutionary models and for assessing the cluster low-to-intermediate mass populations. This study is the first of a series intended to homogeneously reveal open cluster near-infrared sequences.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\U3QVP45T\\2102.html}}
@article{randich_gaia-eso_2018, title = {The {{Gaia-ESO Survey}}: Open Clusters in {{Gaia-DR1}} - {{A}} Way Forward to Stellar Age Calibration,}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Randich, S. and Tognelli, E. and Jackson, R. and Jeffries, R. D. and Degl'Innocenti, S. and Pancino, E. and Fiorentin, P. Re and Spagna, A. and Sacco, G. and Bragaglia, A. and Magrini, L. and Moroni, P. G. Prada and Alfaro, E. and Franciosini, E. and Morbidelli, L. and Roccatagliata, V. and Bouy, H. and Bravi, L. and {Jim{\'e}nez-Esteban}, F. M. and Jordi, C. and Zari, E. and Tautvai{\v s}iene, G. and Drazdauskas, A. and Mikolaitis, S. and Gilmore, G. and Feltzing, S. and Vallenari, A. and Bensby, T. and Koposov, S. and Korn, A. and Lanzafame, A. and Smiljanic, R. and Bayo, A. and Carraro, G. and Costado, M. T. and Heiter, U. and Hourihane, A. and Jofr{\'e}, P. and Lewis, J. and Monaco, L. and Prisinzano, L. and Sbordone, L. and Sousa, S. G. and Worley, C. C. and Zaggia, S.}, year = {2018}, month = apr, journal = {Astronomy \& Astrophysics}, volume = {612}, pages = {A99}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201731738}, urldate = {2019-09-05}, abstract = {\emph{Context.{$<$}i/{$>$} Determination and calibration of the ages of stars, which heavily rely on stellar evolutionary models, are very challenging, while representing a crucial aspect in many astrophysical areas.\emph{Aims.{$<$}i/{$>$} We describe the methodologies that, taking advantage of \emph{Gaia{$<$}i/{$>$}-DR1 and the \emph{Gaia{$<$}i/{$>$}-ESO Survey data, enable the comparison of observed open star cluster sequences with stellar evolutionary models. The final, long-term goal is the exploitation of open clusters as age calibrators.\emph{Methods.{$<$}i/{$>$} We perform a homogeneous analysis of eight open clusters using the \emph{Gaia{$<$}i/{$>$}-DR1 TGAS catalogue for bright members and information from the \emph{Gaia{$<$}i/{$>$}-ESO Survey for fainter stars. Cluster membership probabilities for the \emph{Gaia{$<$}i/{$>$}-ESO Survey targets are derived based on several spectroscopic tracers. The \emph{Gaia{$<$}i/{$>$}-ESO Survey also provides the cluster chemical composition. We obtain cluster parallaxes using two methods. The first one relies on the astrometric selection of a sample of bona fide members, while the other one fits the parallax distribution of a larger sample of TGAS sources. Ages and reddening values are recovered through a Bayesian analysis using the 2MASS magnitudes and three sets of standard models. Lithium depletion boundary (LDB) ages are also determined using literature observations and the same models employed for the Bayesian analysis.\emph{Results.{$<$}i/{$>$} For all but one cluster, parallaxes derived by us agree with those presented in Gaia Collaboration (2017, A\&A, 601, A19), while a discrepancy is found for NGC 2516; we provide evidence supporting our own determination. Inferred cluster ages are robust against models and are generally consistent with literature values.\emph{Conclusions.{$<$}i/{$>$} The systematic parallax errors inherent in the \emph{Gaia{$<$}i/{$>$} DR1 data presently limit the precision of our results. Nevertheless, we have been able to place these eight clusters onto the same age scale for the first time, with good agreement between isochronal and LDB ages where there is overlap. Our approach appears promising and demonstrates the potential of combining \emph{Gaia{$<$}i/{$>$} and ground-based spectroscopic datasets.}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TD72K56J\\Randich et al. - 2018 - The Gaia-ESO Survey open clusters in Gaia-DR1 - A.pdf;C\:\\Users\\Emily\\Zotero\\storage\\D3VRB2RK\\aa31738-17.html}}
@misc{randich_gaia-eso_2022, title = {The {{Gaia-ESO Public Spectroscopic Survey}}: {{Implementation}}, Data Products, Open Cluster Survey, Science, and Legacy}, shorttitle = {The {{Gaia-ESO Public Spectroscopic Survey}}}, author = {Randich, S. and Gilmore, G. and Magrini, L. and Sacco, G. G. and Jackson, R. J. and Jeffries, R. D. and Worley, C. C. and Hourihane, A. and Gonneau, A. and V{\`a}zquez, C. Viscasillas and Franciosini, E. and Lewis, J. R. and Alfaro, E. J. and Prieto, C. Allende and Blomme, T. Bensby R. and Bragaglia, A. and Flaccomio, E. and Fran{\c c}ois, P. and Irwin, M. J. and Koposov, S. E. and Korn, A. J. and Lanzafame, A. C. and Pancino, E. and {Recio-Blanco}, A. and Smiljanic, R. and Van Eck, S. and Zwitter, T. and Asplund, M. and Bonifacio, P. and Feltzing, S. and Binney, J. and Drew, J. and Ferguson, A. M. N. and Micela, G. and Negueruela, I. and Prusti, T. and Rix, H.-W. and Vallenari, A. and Bayo, A. and Bergemann, M. and Biazzo, K. and Carraro, G. and Casey, A. R. and Damiani, F. and Frasca, A. and Heiter, U. and Hill, V. and Jofr{\'e}, P. and {de Laverny}, P. and Lind, K. and Marconi, G. and Martayan, C. and Masseron, T. and Monaco, L. and Morbidelli, L. and Prisinzano, L. and Sbordone, L. and Sousa, S. G. and Zaggia, S. and Adibekyan, V. and Bonito, R. and Caffau, E. and Daflon, S. and Feuillet, D. K. and Gebran, M. and Hern{\'a}ndez, J. I. Gonz{\'a}lez and Guiglion, G. and Herrero, A. and Lobel, A. and Apell{\'a}niz, J. Ma{\'i}z and Merle, T. and Mikolaitis, S. and Montes, D. and Morel, T. and Soubiran, C. and Spina, L. and Tabernero, H. M. and Tautvai{\v s}ien{\.e}, G. and Traven, G. and Valentini, M. and {Van der Swaelmen}, M. and Villanova, S. and Wright, N. J. and Abbas, U. and {B{\o}rsen-Koch}, V. Aguirre and Alves, J. and {Balaguer-N{\'u}nez}, L. and Barklem, P. S. and Barrado, D. and Berlanas, S. R. and Binks, A. S. and Bressan, A. and {Capuzzo--Dolcetta}, R. and Casagrande, L. and Casamiquela, L. and Collins, R. S. and D'Orazi, V. and Dantas, M. L. L. and Debattista, V. P. and {Delgado-Mena}, E. and Di Marcantonio, P. and Drazdauskas, A. and Evans, N. W. and Famaey, B. and Franchini, M. and Fr{\'e}mat, Y. and Friel, E. D. and Fu, X. and Geisler, D. and Gerhard, O. and Solares, E. A. Gonz{\'a}lez and Grebel, E. K. and Albarr{\'a}n, M. L. Guti{\'e}rrez and Hatzidimitriou, D. and Held, E. V. and {Jim{\'e}nez-Esteban}, F. and J{\"o}nsson, H. and Jordi, C. and Khachaturyants, T. and Kordopatis, G. and Kos, J. and Lagarde, N. and Mahy, L. and Mapelli, M. and Marfil, E. and Martell, S. L. and Messina, S. and Miglio, A. and Minchev, I. and Moitinho, A. and Montalban, J. and Monteiro, M. J. P. F. G. and Morossi, C. and Mowlavi, N. and Mucciarelli, A. and Murphy, D. N. A. and Nardetto, N. and Ortolani, S. and Paletou, F. and Palouus, J. and Paunzen, E. and Pickering, J. C. and Quirrenbach, A. and Fiorentin, P. Re and Read, J. I. and Romano, D. and Ryde, N. and Sanna, N. and Santos, W. and Seabroke, G. M. and Spagna, A. and Steinmetz, M. and Stonkut{\'e}, E. and Sutorius, E. and Th{\'e}venin, F. and Tosi, M. and Tsantaki, M. and Vink, J. S. and Wright, N. and Wyse, R. F. G. and Zoccali, M. and Zorec, J. and Zucker, D. B. and Walton, N. A.}, year = {2022}, month = jun, number = {arXiv:2206.02901}, eprint = {2206.02901}, primaryclass = {astro-ph}, institution = {{arXiv}}, doi = {10.48550/arXiv.2206.02901}, urldate = {2022-06-08}, abstract = {In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with the general aim of delivering stellar parameters and elemental abundances for large samples of Galactic stars, complementing Gaia astrometry. Among those surveys, the Gaia-ESO Public Spectroscopic Survey (GES), the only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES on the ESO VLT (both Giraffe and UVES spectrographs), covering all the Milky Way populations, with a special focus on open star clusters. This article provides an overview of the survey implementation (observations, data quality, analysis and its success, data products, and releases), of the open cluster survey, of the science results and potential, and of the survey legacy. A companion article (Gilmore et al.) reviews the overall survey motivation, strategy, Giraffe pipeline data reduction, organisation, and workflow. The GES has determined homogeneous good-quality radial velocities and stellar parameters for a large fraction of its more than 110,000 unique target stars. Elemental abundances were derived for up to 31 elements for targets observed with UVES. Lithium abundances are delivered for about 1/3 of the sample. The analysis and homogenisation strategies have proven to be successful; several science topics have been addressed by the Gaia-ESO consortium and the community, with many highlight results achieved. The final catalogue has been released through the ESO archive at the end of May 2022, including the complete set of advanced data products. In addition to these results, the Gaia-ESO Survey will leave a very important legacy, for several aspects and for many years to come.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{rangwal_interstellar_2017, title = {Interstellar Extinction in Twenty Open Star Clusters}, author = {Rangwal, Geeta and Yadav, R. K. S. and Durgapal, Alok and Bisht, D.}, year = {2017}, journal = {Publications of the Astronomical Society of Australia}, volume = {34}, eprint = {1711.09591}, pages = {e068}, issn = {1323-3580, 1448-6083}, doi = {10.1017/pasa.2017.64}, urldate = {2021-05-17}, abstract = {The interstellar extinction law in twenty open star clusters namely Berkeley 7, Collinder 69, Hogg 10, NGC 2362, Czernik 43, NGC 6530, NGC 6871, Bochum 10, Haffner 18, IC 4996, NGC 2384, NGC 6193, NGC 6618, NGC 7160, Collinder 232, Haffner 19, NGC 2401, NGC 6231, NGC 6823 and NGC 7380 have been studied in the optical and near-IR wavelength ranges. The difference between maximum and minimum values of E(B - V ) indicates the presence of non-uniform extinction in all the clusters except Collinder 69, NGC 2362 and NGC 2384. The colour excess ratios are consistent with a normal extinction law for the clusters NGC 6823, Haffner 18, Haffner 19, NGC 7160, NGC 6193, NGC 2401, NGC 2384, NGC 6871, NGC 7380, Berkeley 7, Collinder 69 and IC 4996. We have found that the differential color-excess {$\increment$}E(B - V ), which may be due to the occurrence of dust and gas inside the clusters, decreases with the age of the clusters. A spatial variation of color excess is found in NGC 6193 in the sense that it decreases from east to west in the cluster region. For the clusters Berkeley 7, NGC 7380 and NGC 6871, a dependence of color excess E(B - V ) with spectral class and luminosity is observed. Eight stars in Collinder 232, four stars in NGC 6530 and one star in NGC 6231 have excess flux in near-IR. This indicates that these stars may have circumstellar material around them.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YPGTLCTA\\Rangwal et al. - 2017 - Interstellar extinction in twenty open star cluste.pdf}}
@article{rao_determination_2021, title = {Determination of {{A}}\$\^+\$ in {{Open Clusters}}}, author = {Rao, Khushboo K. and Vaidya, Kaushar and Agarwal, Manan and Bhattacharya, Souradeep}, year = {2021}, month = feb, journal = {arXiv:2102.07409 [astro-ph]}, eprint = {2102.07409}, primaryclass = {astro-ph}, urldate = {2021-02-24}, abstract = {The sedimentation level of blue straggler stars (BSS) has been shown to be a great tool to investigate the dynamical states of globular clusters (GCs). The area enclosed between the cumulative radial distributions of BSS and a reference population up to the half-mass radius of the clusters, \$A\^+\_\{\textbackslash mathrm\{rh\}\}\$, is known to be a measure of the sedimentation of BSS in GCs. In this work, we calculate \$A\^+\_\{\textbackslash mathrm\{rh\}\}\$ for 12 open clusters (OCs) using main-sequence turn-off stars as a reference population. The BSS as well as the main-sequence turn-off stars for these clusters are identified using the proper motions and parallaxes from the Gaia DR2 data, with spectroscopically confirmed BSS populations for some of these clusters available in the literature. Using the Pearson and Spearman rank correlation coefficients, we find weak correlations between the estimated values of \$A\^+\_\{\textbackslash mathrm\{rh\}\}\$ and other markers of dynamical ages of the clusters, i.e., the number of central relaxations a cluster has experienced since its formation, and the structural parameters of the clusters. Based on statistical tests, we find that these correlations are similar to the corresponding correlations among the less evolved GCs, albeit within large errors.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\WR774TSS\\2102.html}}
@article{rappengluck_palaeolithic_timekeepers_2001, title = {Palaeolithic Timekeepers Looking at the Golden Gate of the Ecliptic; the Lunar Cycle and the Pleiades in the Cave of La-Tete-Du-Lion (Ard\'eche, France) - 21,000 {{BP}}}, author = {Rappengl{\"u}ck, Michael A.}, year = {2001}, month = jan, journal = {Earth Moon and Planets}, volume = {85}, pages = {391--404}, doi = {10.1023/A:1017069411495}}
@article{rastello_effect_2020, title = {Effect of Binarity in Star Cluster Dynamical Mass Determination}, author = {Rastello, Sara and Carraro, Giovanni and {Capuzzo-Dolcetta}, Roberto}, year = {2020}, month = may, journal = {arXiv:2005.03037 [astro-ph]}, eprint = {2005.03037}, primaryclass = {astro-ph}, urldate = {2020-05-08}, abstract = {In this paper we explore the effects that the presence of a fraction of binary stars has in the determination of a star cluster mass via the virial theorem. To reach this aim in an accurate and consistent way, we run a set of simulations using the direct summation, high precision, code NBODY7. By means of this suite of simulations we are able to quantify the overestimate of open-star-cluster-like models' dynamical masses when making a straight application of the virial theorem using available position and radial velocity measurements. The mass inflation caused by the binary 'heating' contribution to the measured velocity dispersion depends, of course, on the initial binary fraction, \$f\_\{b0\}\$ and its following dynamical evolution. For an \$f\_\{b\}\$ (evolved up to 1.5 Gyr) in the range \$8\textbackslash\% - 42\textbackslash\%\$ the overestimate of the mass done using experimentally sounding estimates for the velocity dispersion can be up to a factor 45. We provide a useful fitting formula to correct the dynamical mass determination for the presence of binaries, and underline how neglecting the role of binaries in stellar systems might lead to erroneous conclusions about their total mass budget. If this trend remains valid for larger systems like dwarf spheroidal galaxies, which are still far out of reach for high precision dynamical simulations taking account their binaries, it would imply an incorrect over-estimation of their dark matter content, as inferred by means of available velocity dispersion measurements.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\AKFRWQEP\\2005.html}}
@article{rastello_effect_binarity_2020, title = {Effect of {{Binarity}} in {{Star Cluster Dynamical Mass Determination}}}, author = {Rastello, Sara and Carraro, Giovanni and {Capuzzo-Dolcetta}, Roberto}, year = {2020}, month = jun, journal = {The Astrophysical Journal}, volume = {896}, pages = {152}, issn = {0004-637X}, doi = {10.3847/1538-4357/ab910b}, urldate = {2023-04-27}, abstract = {In this paper we explore the effects that the presence of a fraction of binary stars has in the determination of a star cluster mass via the virial theorem. To reach this aim in an accurate and consistent way, we run a set of simulations using the direct summation, high precision, code NBODY7. By means of this suite of simulations we are able to quantify the overestimate of open-star-cluster-like models' dynamical masses when making a straight application of the virial theorem using available position and radial velocity measurements. The mass inflation caused by the binary "heating" contribution to the measured velocity dispersion depends, of course, on the initial binary fraction, fb0 and its following dynamical evolution. For an fb (evolved up to 1.5 Gyr) in the range 8\%-42\% the overestimate of the mass done using experimentally sounding estimates for the velocity dispersion can be up to a factor of 45. We provide a useful fitting formula to correct the dynamical mass determination for the presence of binaries, and underline how neglecting the role of binaries in stellar systems might lead to erroneous conclusions about their total mass budget. If this trend remains valid for larger systems like dwarf spheroidal galaxies, which are still far out of reach for high-precision dynamical simulations taking their binaries into account, it would imply an incorrect overestimation of their dark matter content, as inferred by means of available velocity dispersion measurements.}, keywords = {1083,154,1567,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Binary stars,N-body simulations,Star clusters}, annotation = {ADS Bibcode: 2020ApJ...896..152R}}
@article{ratzenbock_significance_2022-1, title = {Significance {{Mode Analysis}} ({{SigMA}}) for Hierarchical Structures. {{An}} Application to the {{Sco-Cen OB}} Association}, author = {Ratzenb{\"o}ck, Sebastian and Gro{\ss}schedl, Josefa E. and M{\"o}ller, Torsten and Alves, Jo{\~a}o and Bomze, Immanuel and Meingast, Stefan}, year = {2022}, month = nov, journal = {arXiv e-prints}, pages = {arXiv:2211.14225}, doi = {10.48550/arXiv.2211.14225}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@misc{reback2020pandas, title = {Pandas-Dev/Pandas: {{Pandas}}}, author = {{The pandas development team}}, year = {2020}, month = feb, doi = {10.5281/zenodo.3509134}, howpublished = {Zenodo}}
@article{reddy_evolution_2016, title = {The Evolution of the {{Milky Way}}: New Insights from Open Clusters}, shorttitle = {The Evolution of the {{Milky Way}}}, author = {Reddy, Arumalla B. S. and Lambert, David L. and Giridhar, Sunetra}, year = {2016}, month = dec, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {463}, number = {4}, pages = {4366--4382}, issn = {0035-8711}, doi = {10.1093/mnras/stw2287}, urldate = {2019-09-03}, abstract = {Abstract. We have collected high-dispersion echelle spectra of red giant members in the 12 open clusters (OCs) and derived stellar parameters and chemical abun}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\KH5VP7IE\\Reddy et al. - 2016 - The evolution of the Milky Way new insights from .pdf;C\:\\Users\\Emily\\Zotero\\storage\\9Q8TT9I9\\2646519.html}}
@article{reid_trigonometric_parallaxes_2014, title = {Trigonometric Parallaxes of High Mass Star Forming Regions: {{The}} Structure and Kinematics of the Milky Way}, author = {Reid, M. J. and Menten, K. M. and Brunthaler, A. and Zheng, X. W. and Dame, T. M. and Xu, Y. and Wu, Y. and Zhang, B. and Sanna, A. and Sato, M. and Hachisuka, K. and Choi, Y. K. and Immer, K. and Moscadelli, L. and Rygl, K. L. J. and Bartkiewicz, A.}, year = {2014}, month = mar, volume = {783}, number = {2}, eprint = {1401.5377}, primaryclass = {astro-ph.GA}, pages = {130}, doi = {10.1088/0004-637X/783/2/130}, archiveprefix = {arxiv}, keywords = {Astrophysics - Galaxy Astrophysics,Galaxy: fundamental parameters,Galaxy: kinematics and dynamics,Galaxy: structure,gravitational waves,parallaxes,stars: formation}}
@article{reino_gaia_study_2018, title = {A {{Gaia}} Study of the {{Hyades}} Open Cluster}, author = {Reino, Stella and {de Bruijne}, Jos and Zari, Eleonora and {d'Antona}, Francesca and Ventura, Paolo}, year = {2018}, month = jul, volume = {477}, number = {3}, eprint = {1804.00759}, primaryclass = {astro-ph.GA}, pages = {3197--3216}, doi = {10.1093/mnras/sty793}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2018MNRAS.477.3197R}, archiveprefix = {arxiv}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,open clusters and associations: individual: Hyades,stars: distances,stars: fundamental parameters}}
@article{reis_effectively_2019, title = {Effectively Using Unsupervised Machine Learning in next Generation Astronomical Surveys}, author = {Reis, Itamar and Rotman, Michael and Poznanski, Dovi and Prochaska, J. Xavier and Wolf, Lior}, year = {2019}, month = nov, journal = {arXiv:1911.06823 [astro-ph]}, eprint = {1911.06823}, primaryclass = {astro-ph}, urldate = {2019-11-19}, abstract = {In recent years many works have shown that unsupervised Machine Learning (ML) can help detect unusual objects and uncover trends in large astronomical datasets, but a few challenges remain. We show here, for example, that different methods, or even small variations of the same method, can produce significantly different outcomes. While intuitively somewhat surprising, this can naturally occur when applying unsupervised ML to highly dimensional data, where there can be many reasonable yet different answers to the same question. In such a case the outcome of any single unsupervised ML method should be considered a sample from a conceivably wide range of possibilities. We therefore suggest an approach that eschews finding an optimal outcome, instead facilitating the production and examination of many valid ones. This can be achieved by incorporating unsupervised ML into data visualisation portals. We present here such a portal that we are developing, applied to the sample of SDSS spectra of galaxies. The main feature of the portal is interactive 2D maps of the data. Different maps are constructed by applying dimensionality reduction to different subspaces of the data, so that each map contains different information that in turn gives a different perspective on the data. The interactive maps are intuitive to use, and we demonstrate how peculiar objects and trends can be detected by means of a few button clicks. We believe that including tools in this spirit in next generation astronomical surveys will be important for making unexpected discoveries, either by professional astronomers or by citizen scientists, and will generally enable the benefits of visual inspection even when dealing with very complex and extensive datasets. Our portal is available online at galaxyportal.space.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\VR8QKSTB\\1911.html}}
@article{renzini_formation_2022, title = {The {{Formation}} of {{Globular Clusters}} as a {{Case}} of {{Overcooling}}}, author = {Renzini, Alvio and Marino, Anna F. and Milone, Antonino P.}, year = {2022}, month = mar, journal = {arXiv:2203.03002 [astro-ph]}, eprint = {2203.03002}, primaryclass = {astro-ph}, urldate = {2022-03-08}, abstract = {Driven by recent observational findings, we select massive interactive binaries as the most suitable among the existing candidates for producing the chemical patterns typical of multiple populations of Galactic globular clusters. Still, to avoid supernova contamination we are further driven to endorse the notion that above a critical mass stars fail to produce supernova events, but rather eventually sink into black holes without ejecting much energy and heavy metals. This assumption has the attractive implication of suppressing star formation feedback for some 5--10 million years, in practice leading to runaway star formation, analog to \{\textbackslash it overcooling\} that in absence of feedback would have turned most baryons into stars in the early Universe. Under such conditions, multiple episodes of stars formation, incorporating binary star ejecta from previous episodes, appear to be unavoidable, thus accounting for the ubiquity of the multiple population phenomenon in globular clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\LT6BKMTU\\2203.html}}
@article{riello_gaia_2018, title = {Gaia {{Data Release}} 2 - {{Processing}} of the Photometric Data}, author = {Riello, M. and Angeli, F. De and Evans, D. W. and Busso, G. and Hambly, N. C. and Davidson, M. and Burgess, P. W. and Montegriffo, P. and Osborne, P. J. and Kewley, A. and Carrasco, J. M. and Fabricius, C. and Jordi, C. and Cacciari, C. and van Leeuwen, F. and Holland, G.}, year = {2018}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {616}, pages = {A3}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201832712}, urldate = {2019-09-16}, abstract = {\emph{Context.{$<$}i/{$>$} The second \emph{Gaia{$<$}i/{$>$} data release is based on 22 months of mission data with an average of 0.9 billion individual CCD observations per day. A data volume of this size and granularity requires a robust and reliable but still flexible system to achieve the demanding accuracy and precision constraints that \emph{Gaia{$<$}i/{$>$} is capable of delivering.\emph{Aims.{$<$}i/{$>$} We aim to describe the input data, the treatment of blue photometer/red photometer (BP/RP) low-resolution spectra required to produce the integrated \emph{G{$<$}i/{$>$}\textsubscript{BP{$<$}sub/{$>$} and \emph{G{$<$}i/{$>$}\textsubscript{RP{$<$}sub/{$>$} fluxes, the process used to establish the internal \emph{Gaia{$<$}i/{$>$} photometric system, and finally, the generation of the mean source photometry from the calibrated epoch data for \emph{Gaia{$<$}i/{$>$} DR2.\emph{Methods.{$<$}i/{$>$} The internal \emph{Gaia{$<$}i/{$>$} photometric system was initialised using an iterative process that is solely based on \emph{Gaia{$<$}i/{$>$} data. A set of calibrations was derived for the entire \emph{Gaia{$<$}i/{$>$} DR2 baseline and then used to produce the final mean source photometry. The photometric catalogue contains 2.5 billion sources comprised of three different grades depending on the availability of colour information and the procedure used to calibrate them: 1.5 billion gold, 144 million silver, and 0.9 billion bronze. These figures reflect the results of the photometric processing; the content of the data release will be different due to the validation and data quality filters applied during the catalogue preparation. The photometric processing pipeline, PhotPipe, implements all the processing and calibration workflows in terms of Map/Reduce jobs based on the Hadoop platform. This is the first example of a processing system for a large astrophysical survey project to make use of these technologies.\emph{Results.{$<$}i/{$>$} The improvements in the generation of the integrated \emph{G{$<$}i/{$>$}\textendash band fluxes, in the attitude modelling, in the cross-matching, and and in the identification of spurious detections led to a much cleaner input stream for the photometric processing. This, combined with the improvements in the definition of the internal photometric system and calibration flow, produced high-quality photometry. Hadoop proved to be an excellent platform choice for the implementation of PhotPipe in terms of overall performance, scalability, downtime, and manpower required for operations and maintenance.}}}}}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\UBE4XS7U\\Riello et al_2018_Gaia Data Release 2 - Processing of the photometric data.pdf;C\:\\Users\\Emily\\Zotero\\storage\\6AP97CGP\\aa32712-18.html}}
@article{riello_gaia_2021, title = {Gaia {{Early Data Release}} 3: {{Photometric}} Content and Validation}, shorttitle = {Gaia {{Early Data Release}} 3}, author = {Riello, M. and De Angeli, F. and Evans, D. W. and Montegriffo, P. and Carrasco, J. M. and Busso, G. and Palaversa, L. and Burgess, P. W. and Diener, C. and Davidson, M. and Rowell, N. and Fabricius, C. and Jordi, C. and Bellazzini, M. and Pancino, E. and Harrison, D. L. and Cacciari, C. and {van Leeuwen}, F. and Hambly, N. C. and Hodgkin, S. T. and Osborne, P. J. and Altavilla, G. and Barstow, M. A. and Brown, A. G. A. and Castellani, M. and Cowell, S. and De Luise, F. and Gilmore, G. and Giuffrida, G. and Hidalgo, S. and Holland, G. and Marinoni, S. and Pagani, C. and Piersimoni, A. M. and Pulone, L. and Ragaini, S. and Rainer, M. and Richards, P. J. and Sanna, N. and Walton, N. A. and Weiler, M. and Yoldas, A.}, year = {2021}, journal = {Astronomy \& Astrophysics}, volume = {649}, eprint = {2012.01916}, pages = {A3}, urldate = {2021-01-04}, abstract = {Gaia Early Data Release 3 contains astrometry and photometry results for about 1.8 billion sources based on observations collected by the ESA Gaia satellite during the first 34 months of operations. This paper focuses on the photometric content, describing the input data, the algorithms, the processing, and the validation of the results. Particular attention is given to the quality of the data and to a number of features that users may need to take into account to make the best use of the EDR3 catalogue. The treatment of the BP and RP background has been updated to include a better estimation of the local background, and the detection of crowding effects has been used to exclude affected data from the calibrations. The photometric calibration models have also been updated to account for flux loss over the whole magnitude range. Significant improvements in the modelling and calibration of the point and line spread functions have also helped to reduce a number of instrumental effects that were still present in DR2. EDR3 contains 1.806 billion sources with G-band photometry and 1.540 billion sources with BP and RP photometry. The median uncertainty in the G-band photometry, as measured from the standard deviation of the internally calibrated mean photometry for a given source, is 0.2 mmag at magnitude G=10 to 14, 0.8 mmag at G=17, and 2.6 mmag at G=19. The significant magnitude term found in the Gaia DR2 photometry is no longer visible, and overall there are no trends larger than 1 mmag/mag. Using one passband over the whole colour and magnitude range leaves no systematics above the 1\% level in magnitude in any of the bands, and a larger systematic is present for a very small sample of bright and blue sources. A detailed description of the residual systematic effects is provided. Overall the quality of the calibrated mean photometry in EDR3 is superior with respect to DR2 for all bands.}, archiveprefix = {arxiv}, keywords = {\_tablet,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6GHKVJGC\\2012.html}}
@article{rix_selection_functions_2021, title = {Selection {{Functions}} in {{Astronomical Data Modeling}}, with the {{Space Density}} of {{White Dwarfs}} as a {{Worked Example}}}, author = {Rix, Hans-Walter and Hogg, David W. and Boubert, Douglas and Brown, Anthony G. A. and Casey, Andrew and Drimmel, Ronald and Everall, Andrew and Fouesneau, Morgan and {Price-Whelan}, Adrian M.}, year = {2021}, month = oct, journal = {The Astronomical Journal}, volume = {162}, pages = {142}, issn = {0004-6256}, doi = {10.3847/1538-3881/ac0c13}, urldate = {2023-04-25}, abstract = {Statistical studies of cataloged object properties are central to astrophysics. But one cannot model those objects' population properties without the sample's selection function, the quantitative understanding of which objects could have ended up in such a catalog. As didactic introductions to this topic are scarce in the astrophysical literature, we provide one here, addressing the following questions: What is a selection function? On what arguments q should it depend? Over what domain must a selection function be defined? What simplifying approximations can be made? And, how is a selection function used in "modeling"? We argue that volume-complete samples, limited by the faintest objects, reflect a highly suboptimal selection function, needlessly reducing the number of bright and usually rare sample members. We illustrate these points by a worked example: github.com/gaia-unlimited/WD-selection-function, deriving the space density of white dwarfs (WDs) in the Galactic neighborhood as a function of their luminosity and color, {$\Phi$}0(MG, (B - R)) in [mag-2 pc-3]. We construct a sample \$\{ \textbackslash mathcal C \}\$ of 105 presumed WDs through straightforward selection cuts on the Gaia EDR3 catalog in magnitude, color, and parallax, q = (G, (B - R), {$\varpi$}). We then combine a simple model for {$\Phi$}0 with this selection function's \$\{S\}\_\{\{ \textbackslash mathcal C \}\}(\{\textbackslash boldsymbol\{q\}\})\$ effective survey volume to estimate {$\Phi$}0(MG, (B - R)) precisely and robustly against the detailed choices for \$\{S\}\_\{\{ \textbackslash mathcal C \}\}(\{\textbackslash boldsymbol\{q\}\})\$ . This resulting WD luminosity-color function {$\Phi$}0(MG, (B - R)) differs dramatically from the initial number density distribution in the luminosity-color plane: by orders of magnitude in density and by four magnitudes in density peak location.}, keywords = {1858,Astronomy data analysis,Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, annotation = {ADS Bibcode: 2021AJ....162..142R}}
@article{robitaille_astropy_2013, title = {Astropy: {{A}} Community {{Python}} Package for Astronomy}, shorttitle = {Astropy}, author = {Robitaille, Thomas P. and Tollerud, Erik J. and Greenfield, Perry and Droettboom, Michael and Bray, Erik and Aldcroft, Tom and Davis, Matt and Ginsburg, Adam and {Price-Whelan}, Adrian M. and Kerzendorf, Wolfgang E. and Conley, Alexander and Crighton, Neil and Barbary, Kyle and Muna, Demitri and Ferguson, Henry and Grollier, Fr{\'e}d{\'e}ric and Parikh, Madhura M. and Nair, Prasanth H. and G{\"u}nther, Hans M. and Deil, Christoph and Woillez, Julien and Conseil, Simon and Kramer, Roban and Turner, James E. H. and Singer, Leo and Fox, Ryan and Weaver, Benjamin A. and Zabalza, Victor and Edwards, Zachary I. and Bostroem, K. Azalee and Burke, D. J. and Casey, Andrew R. and Crawford, Steven M. and Dencheva, Nadia and Ely, Justin and Jenness, Tim and Labrie, Kathleen and Lim, Pey Lian and Pierfederici, Francesco and Pontzen, Andrew and Ptak, Andy and Refsdal, Brian and Servillat, Mathieu and Streicher, Ole}, year = {2013}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {558}, pages = {A33}, publisher = {{EDP Sciences}}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201322068}, urldate = {2020-06-24}, abstract = {We present the first public version (v0.2) of the open-source and community-developed Python package, Astropy. This package provides core astronomy-related functionality to the community, including support for domain-specific file formats such as flexible image transport system (FITS) files, Virtual Observatory (VO) tables, and common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions. Significant functionality is under activedevelopment, such as a model fitting framework, VO client and server tools, and aperture and point spread function (PSF) photometry tools. The core development team is actively making additions and enhancements to the current code base, and we encourage anyone interested to participate in the development of future Astropy versions.}, copyright = {\textcopyright{} ESO, 2013}, langid = {english}}
@article{rodriguez_modeling_2021, title = {Modeling {{Dense Star Clusters}} in the {{Milky Way}} and {{Beyond}} with the {{Cluster Monte Carlo Code}}}, author = {Rodriguez, Carl L. and Weatherford, Newlin C. and Coughlin, Scott C. and Seoane, Pau Amaro and Breivik, Katelyn and Chatterjee, Sourav and Fragione, Giacomo and K{\i}ro{\u g}lu, Fulya and Kremer, Kyle and Rui, Nicholas Z. and Ye, Claire S. and Zevin, Michael and Rasio, Frederic A.}, year = {2021}, month = oct, journal = {arXiv:2106.02643 [astro-ph]}, eprint = {2106.02643}, primaryclass = {astro-ph}, urldate = {2021-10-28}, abstract = {We describe the public release of the Cluster Monte Carlo Code (CMC) a parallel, star-by-star \$N\$-body code for modeling dense star clusters. CMC treats collisional stellar dynamics using H\textbackslash 'enon's method, where the cumulative effect of many two-body encounters is statistically reproduced as a single effective encounter between nearest-neighbor particles on a relaxation timescale. The star-by-star approach allows for the inclusion of additional physics, including strong gravitational three- and four-body encounters, two-body tidal and gravitational-wave captures, mass loss in arbitrary galactic tidal fields, and stellar evolution for both single and binary stars. The public release of CMC is pinned directly to the COSMIC population synthesis code, allowing dynamical star cluster simulations and population synthesis studies to be performed using identical assumptions about the stellar physics and initial conditions. As a demonstration, we present two examples of star cluster modeling: first, we perform the largest (\$N = 10\^8\$) star-by-star \$N\$-body simulation of a Plummer sphere evolving to core collapse, reproducing the expected self-similar density profile over more than 15 orders of magnitude; second, we generate realistic models for typical globular clusters, and we show that their dynamical evolution can produce significant numbers of black hole mergers with masses greater than those produced from isolated binary evolution (such as GW190521, a recently reported merger with component masses in the pulsational pair-instability mass gap).}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NCF9YEGV\\2106.html}}
@article{roeser_ppmxl_catalog_2010, title = {The {{PPMXL Catalog}} of {{Positions}} and {{Proper Motions}} on the {{ICRS}}. {{Combining USNO-B1}}.0 and the {{Two Micron All Sky Survey}} ({{2MASS}})}, author = {Roeser, S. and Demleitner, M. and Schilbach, E.}, year = {2010}, month = jun, journal = {The Astronomical Journal}, volume = {139}, pages = {2440--2447}, issn = {0004-6256}, doi = {10.1088/0004-6256/139/6/2440}, urldate = {2023-04-06}, abstract = {USNO-B1.0 and the Two Micron All Sky Survey (2MASS) are the most widely used all-sky surveys. However, 2MASS has no proper motions at all, and USNO-B1.0 published only relative, not absolute (i.e., on the International Celestial Reference Frame (ICRS), proper motions. We performed a new determination of mean positions and proper motions on the ICRS system by combining USNO-B1.0 and 2MASS astrometry. This catalog is called PPMXL (VO access to the catalog is possible via http://vo.uni-hd.de/ppmxl), and it aims to be completed from the brightest stars down to about V {$\approx$} 20 all sky. PPMXL contains about 900 million objects, some 410 million with 2MASS photometry, and is the largest collection of ICRS proper motions at present. As representative for the ICRS, we chose PPMX. The recently released UCAC3 could not be used because we found plate-dependent distortions in its proper motion system north of -20\textdegree{} declination. UCAC3 served as an intermediate system for {$\delta$} {$<$}= -20\textdegree. The resulting typical individual mean errors of the proper motions range from 4 mas yr-1 to more than 10 mas yr-1 depending on observational history. The mean errors of positions at epoch 2000.0 are 80-120 mas, if 2MASS astrometry could be used, 150-300 mas else. We also give correction tables to convert USNO-B1.0 observations of, e.g., minor planets to the ICRS system.}, keywords = {astrometry,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,catalogs,Galaxy: kinematics and dynamics,proper motions}, annotation = {ADS Bibcode: 2010AJ....139.2440R}}
@article{roland_assessing_2020, title = {Assessing Membership Projection Errors in Star Forming Regions}, author = {Roland, Timoth{\'e} and Boily, Christian M. and Cambr{\'e}sy, Laurent}, year = {2020}, month = nov, journal = {arXiv:2010.10555 [astro-ph]}, eprint = {2010.10555}, primaryclass = {astro-ph}, urldate = {2020-11-30}, abstract = {Young stellar clusters harbour complex spatial structures emerging from the star formation process. Identifying stellar over-densities is a key step to constrain better how these structures are formed. The high accuracy of distances derived from Gaia DR2 parallaxes yet do not allow to locate with certainty individual stars within clusters of size \$\textbackslash approx 1\textbackslash, \textbackslash rm\{pc\}\$. In this work, we explore how such uncertainty in distance estimates can lead to the misidentification of membership of sub-clusters selected by the minimum spanning tree (MST) algorithm. Our goal is to assess how this impacts their estimated properties. Using N-body simulations, we build Gravity-Driven Fragmentation (GDF) models that reproduce self-consistently the early stellar configurations of a star forming region. Stellar groups are then identified both in 3- and 2-dimensions by the MST algorithm, representing respectively an ideal and an inaccurate identification. We compare the properties derived of these resulting groups, to assess the systematic bias introduced by projection and incompleteness. We show that in such fragmented configurations, the dynamical mass of groups identified in projection is systematically underestimated compared to those of groups identified in 3D. This systematic error is statistically of \$50\textbackslash\%\$ for more than half of the groups and reach \$100\textbackslash\%\$ in a quarter of them. Adding incompleteness further increases this bias. These results challenge our ability to identify accurately sub-clusters in most nearby star forming regions where distance estimate uncertainties are comparable to the size of the region. New clump finding methods have to tackle this issue in order to define better the dynamical state of these substructures.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{rosenberg_uber_zusammenhang_1910, title = {\"Uber Den {{Zusammenhang}} von {{Helligkeit}} Und {{Spektraltypus}} in Den {{Plejaden}}}, author = {Rosenberg, H.}, year = {1910}, month = oct, journal = {Astronomische Nachrichten}, volume = {186}, number = {5}, pages = {71}, doi = {10.1002/asna.19101860503}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1910AN....186...71R}}
@article{röser_hyades_tidal_2019, title = {Hyades Tidal Tails Revealed by {{Gaia DR2}}}, author = {R{\"o}ser, Siegfried and Schilbach, Elena and Goldman, Bertrand}, year = {2019}, month = jan, volume = {621}, eprint = {1811.03845}, primaryclass = {astro-ph.SR}, pages = {L2}, doi = {10.1051/0004-6361/201834608}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general,open clusters and associations: individual: Hyades,parallaxes,proper motions}}
@article{röser_praesepe_ngc_2019, title = {Praesepe ({{NGC}} 2632) and Its Tidal Tails}, author = {R{\"o}ser, Siegfried and Schilbach, Elena}, year = {2019}, month = jul, volume = {627}, eprint = {1903.08610}, primaryclass = {astro-ph.SR}, pages = {A4}, doi = {10.1051/0004-6361/201935502}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,individual: Praesepe,open clusters and associations}}
@article{russell_relations_spectra_1914, title = {Relations between the Spectra and Other Characteristics of the Stars}, author = {Russell, Henry Norris}, year = {1914}, month = may, journal = {Popular Astronomy}, volume = {22}, pages = {275--294}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/1914PA.....22..275R}}
@article{rybizki_classifier_2022, title = {A Classifier for Spurious Astrometric Solutions in {{Gaia EDR3}}}, author = {Rybizki, Jan and Green, Gregory and Rix, Hans-Walter and Demleitner, Markus and Zari, Eleonora and Udalski, Andrzej and Smart, Richard L. and Gould, Andy}, year = {2022}, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {510}, number = {2}, pages = {2597--2616}, urldate = {2021-02-01}, abstract = {The Gaia mission is delivering exquisite astrometric data for 1.47 billion sources, which are revolutionizing many fields in astronomy. For a small fraction of these sources the astrometric solutions are poor, and the reported values and uncertainties may not apply. For many analyses it is important to recognize and excise these spurious results, commonly done by means of quality flags in the Gaia catalog. Here we devise and apply a path to separating 'good' from 'bad' astrometric solutions that is an order-of-magnitude cleaner than any single flag: we achieve a purity of 99.7\% and a completeness of 97.6\% as validated on our test data. We devise an extensive sample of manifestly bad astrometric solutions: sources whose inferred parallax is 'negative' at {$>$}= 4.5 sigma; and a corresponding sample of presumably good solutions: the sources in HEALPix patches of the sky that do not contain extremely negative parallaxes. We then train a neural net that uses 14 pertinent Gaia catalog entries to discriminate these two samples, captured in a single 'astrometric fidelity' parameter. An extensive and diverse set of verification tests show that our approach to assessing astrometric fidelity works very cleanly also in the regime where no negative parallaxes are involved; its main limitations are in the very low S/N regime. Our astrometric fidelities for all EDR3 can be queried via the Virtual Observatory. In the spirit of open science, we make our code and training/validation data public, so that our results can be easily reproduced.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{rybizki_gaia_2020, title = {A {{Gaia}} Early {{DR3}} Mock Stellar Catalog: {{Galactic}} Prior and Selection Function}, shorttitle = {A {{Gaia}} Early {{DR3}} Mock Stellar Catalog}, author = {Rybizki, Jan and Demleitner, Markus and {Bailer-Jones}, Coryn and Tio, Piero Dal and {Cantat-Gaudin}, Tristan and Fouesneau, Morgan and Chen, Yang and Andrae, Rene and Girardi, Leo and Sharma, Sanjib}, year = {2020}, month = apr, journal = {arXiv:2004.09991 [astro-ph]}, eprint = {2004.09991}, primaryclass = {astro-ph}, urldate = {2020-04-22}, abstract = {We present a mock stellar catalog, matching in volume, depth and data model the content of the planned Gaia early data release 3 (Gaia EDR3). We have generated our catalog (GeDR3mock) using galaxia, a tool to sample stars from an underlying Milky Way (MW) model or from N-body data. We used an updated Besan\textbackslash c\{c\}on Galactic model together with the latest PARSEC stellar evolutionary tracks, now also including white dwarfs. We added the Magellanic clouds and realistic open clusters with internal rotation. We empirically modelled uncertainties based on Gaia DR2 (GDR2) and scaled them according to the longer baseline in Gaia EDR3. The apparent magnitudes were reddened according to a new selection of 3D extinction maps. To help with the Gaia selection function we provide all-sky magnitude limit maps in G and BP for a few relevant GDR2 subsets together with the routines to produce these maps for user-defined subsets. We supplement the catalog with photometry and extinctions in non-Gaia bands. The catalog is available in the Virtual Observatory and can be queried just like the actual Gaia EDR3 will be. We highlight a few capabilities of the Astronomy Data Query Language (ADQL) with educative catalog queries. We use the data extracted from those queries to compare GeDR3mock to GDR2, which emphasises the importance of adding observational noise to the mock data. Since the underlying truth, e.g. stellar parameters, is know in GeDR3mock, it can be used to construct priors as well as mock data tests for parameter estimation. All code, models and data used to produce GeDR3mock are linked and contained in galaxia\_wrap, a python package, representing a fast galactic forward model, able to project MW models and N-body data into realistic Gaia observables.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}}
@article{ryu_wise_2018, title = {A {{WISE Survey}} of {{New Star Clusters}} in the {{Central Plane Region}} of the {{Milky Way}}}, author = {Ryu, Jinhyuk and Lee, Myung Gyoon}, year = {2018}, month = apr, journal = {The Astrophysical Journal}, volume = {856}, pages = {152}, issn = {['0004-637X']}, doi = {10.3847/1538-4357/aab1ff}, urldate = {2019-11-18}, abstract = {We present the discovery of new star clusters in the central plane region (| l| \< 30\^\textbackslash circ and | b| \< 6\^\textbackslash circ ) of the Milky Way. In order to overcome the extinction problem and the spatial limit of previous surveys, we use the Wide-field Infrared Survey Explorer (WISE) data to find clusters. We also use other infrared survey data in the archive for additional analysis. We find 923 new clusters, of which 202 clusters are embedded clusters. These clusters are concentrated toward the Galactic plane and show a symmetric distribution with respect to the Galactic latitude. The embedded clusters show a stronger concentration to the Galactic plane than the nonembedded clusters. The new clusters are found more in the first Galactic quadrant, while previously known clusters are found more in the fourth Galactic quadrant. The spatial distribution of the combined sample of known clusters and new clusters is approximately symmetric with respect to the Galactic longitude. We estimate reddenings, distances, and relative ages of the 15 class A clusters using theoretical isochrones. Ten of them are relatively old (age \>800 Myr) and five are young (age {$\approx$}4 Myr).}, langid = {english}, keywords = {\_tablet}}
@article{sana_mad_view_2010, title = {A {{MAD}} View of {{Trumpler}} 14}, author = {Sana, H. and Momany, Y. and Gieles, M. and Carraro, G. and Beletsky, Y. and Ivanov, V. D. and {de Silva}, G. and James, G.}, year = {2010}, month = jun, journal = {Astronomy and Astrophysics}, volume = {515}, pages = {A26}, issn = {0004-6361}, doi = {10.1051/0004-6361/200913688}, urldate = {2023-05-01}, abstract = {We present adaptive optics (AO) near-infrared observations of the core of the Tr 14 cluster in the Carina region obtained with the ESO multi-conjugate AO demonstrator, MAD. Our campaign yields AO-corrected observations with an image quality of about 0.2\textasciiacute\textasciiacute{} across the 2\textasciiacute{} field of view, which is the widest AO mosaic ever obtained. We detected almost 2000 sources spanning a dynamic range of 10 mag. The pre-main sequence (PMS) locus in the colour-magnitude diagram is well reproduced by Palla \& Stahler isochrones with an age of 3 to 5\texttimes 105 yr, confirming the very young age of the cluster. We derive a very high (deprojected) central density n0 \textasciitilde{} 4.5({$\pm$}0.5)\texttimes 104 pc-3 and estimate the total mass of the cluster to be about \textasciitilde 4.3+3.3-1.5\texttimes 103 M\_{$\odot$}, although contamination of the field of view might have a significant impact on the derived mass. We show that the pairing process is largely dominated by chance alignment so that physical pairs are difficult to disentangle from spurious ones based on our single epoch observation. Yet, we identify 150 likely bound pairs, 30\% of these with a separation smaller than 0.5\textasciiacute\textasciiacute{} (\textasciitilde 1300 AU). We further show that at the 2{$\sigma$} level massive stars have more companions than lower-mass stars and that those companions are respectively brighter on average, thus more massive. Finally, we find some hints of mass segregation for stars heavier than about 10 M\_{$\odot$}. If confirmed, the observed degree of mass segregation could be explained by dynamical evolution, despite the young age of the cluster. Based on observations obtained with the MCAO Demonstrator (MAD) at the VLT Melipal Nasmyth focus (ESO public data release).Full Tables [see full textsee full text] and [see full textsee full text] are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/515/A26}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics,binaries: visual,instrumentation: adaptive optics,open clusters and associations: individual: Tr 14,stars: early-type,stars: pre-main sequence}, annotation = {ADS Bibcode: 2010A\&A...515A..26S}}
@article{sanchez_catalogue_2020, title = {A Catalogue of Open Cluster Radii Determined from {{Gaia}} Proper Motions}, author = {Sanchez, Nestor and Alfaro, Emilio and {Lopez-Martinez}, Fatima}, year = {2020}, month = may, journal = {arXiv:2005.05924 [astro-ph]}, eprint = {2005.05924}, primaryclass = {astro-ph}, urldate = {2020-05-13}, abstract = {In this work we improve a previously published method to calculate in a reliable way the radius of an open cluster. The method is based on the behaviour of stars in the proper motion space as the sampling changes in the position space. Here we describe the new version of the method and show its performance and robustness. Additionally, we apply it to a large number of open clusters using data from Gaia DR2 to generate a catalogue of 401 clusters with reliable radius estimations. The range of obtained apparent radii goes from Rc=1.4+-0.1 arcmin (for the cluster FSR 1651) to Rc=25.5+-3.5 arcmin (for NGC\textasciitilde 2437). Cluster linear sizes follow very closely a lognormal distribution with a mean characteristic radius of Rc=3.7 pc, and its high radius tail can be fitted by a power law as N \textbackslash propto Rc\^(-3.11+-0.35). Additionally, we find that number of members, cluster radius and age follow the relationship Nc \textbackslash propto Rc\^(1.2+-0.1) Tc\^(-1.9+-0.4) where the younger and more extensive the cluster, the more members it presents. The proposed method is not sensitive to low density or irregular spatial distributions of stars and, therefore, is a good alternative or complementary procedure to calculate open cluster radii not having previous information on star memberships.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{santos_jr_viscacha_2020, title = {The {{VISCACHA}} Survey -- {{II}}. {{Structure}} of Star Clusters in the {{Magellanic Clouds}} Periphery}, author = {Santos Jr., J. F. C. and Maia, F. F. S. and Dias, B. and Kerber, L. de O. and Piatti, A. E. and Bica, E. and Angelo, M. S. and Minniti, D. and {P{\'e}rez-Villegas}, A. and {Roman-Lopes}, A. and Westera, P. and Fraga, L. and Quint, B. and Sanmartim, D.}, year = {2020}, month = aug, journal = {arXiv:2008.04399 [astro-ph]}, eprint = {2008.04399}, primaryclass = {astro-ph}, urldate = {2020-08-12}, abstract = {We provide a homogeneous set of structural parameters of 83 star clusters located at the periphery of the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC). The clusters' stellar density and surface brightness profiles were built from deep, AO assisted optical images, and uniform analysis techniques. The structural parameters were obtained from King and Elson et al. model fittings. Integrated magnitudes and masses (for a subsample) are also provided. The sample contains mostly low surface brightness clusters with distances between 4.5 and 6.5 kpc and between 1 and 6.5 kpc from the LMC and SMC centres, respectively. We analysed their spatial distribution and structural properties, comparing them with those of inner clusters. Half-light and Jacobi radii were estimated, allowing an evaluation of the Roche volume tidal filling. We found that: (i) for our sample of LMC clusters, the tidal radii are, on average, larger than those of inner clusters from previous studies; (ii) the core radii dispersion tends to be greater for LMC clusters located towards the southwest, with position angles of \$\textbackslash sim\$200 degrees and about \$\textbackslash sim\$5 degrees from the LMC centre, i.e., those LMC clusters nearer to the SMC; (iii) the core radius evolution for clusters with known age is similar to that of inner clusters; (iv) SMC clusters with galactocentric distances closer than 4 kpc are overfilling; (v) the recent Clouds collision did not leave marks on the LMC clusters' structure that our analysis could reveal.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\L2IILFTT\\2008.html}}
@article{santos-silva_canis_2021, title = {Canis {{Major OB1}} Stellar Group Contents Revealed by {{Gaia}}}, author = {{Santos-Silva}, T. and Perottoni, H. D. and {Almeida-Fernandes}, F. and {Gregorio-Hetem}, J. and {Jatenco-Pereira}, V. and {Mendes de Oliveira}, C. and Montmerle, T. and Bica, E. and Bonatto, C. and Monteiro, H. and Dias, W. S. and Barbosa, C. E. and Fernandes, B. and Galli, P. A. B. and Borges Fernandes, M. and Kanaan, A. and Ribeiro, T. and Schoenell, W.}, year = {2021}, month = nov, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {508}, pages = {1033--1055}, issn = {0035-8711}, doi = {10.1093/mnras/stab2409}, urldate = {2022-03-28}, abstract = {Canis Major OB1 (CMa OB1) is a Galactic stellar association with a very intriguing star-formation scenario. There are more than two dozen known star clusters in its line of sight, but it is not clear which ones are physically associated with CMa OB1. We use a clustering code that employs five-dimensional data from the Gaia DR2 catalogue to identify physical groups and obtain their astrometric parameters and, in addition, we use two different isochrone-fitting methods to estimate the ages of these groups. We find 15 stellar groups with distances between 570 and 1650 pc, including 10 previously known and five new open cluster candidates. Four groups, precisely the youngest ones ({$<$} 20 Myr), CMa05, CMa06, CMa07, and CMa08, are confirmed to be part of CMa OB1. We find that CMa08, a new cluster candidate, may be the progenitor cluster of runaway stars. CMa06 coincides with the well-studied CMa R1 star-forming region. While CMa06 is still forming stars, due to the remaining material of the molecular cloud associated with the Sh 2-262 nebula, CMa05, CMa07, and CMa08 seem to be in more evolved stages of evolution, with no recent star-forming activity. The properties of these CMa OB1 physical groups fit well in a monolithic scenario of star formation, with a common formation mechanism, and having suffered multiple episodes of star formation. This suggests that the hierarchical model alone, which explains the populations of other parts of the same association, is not sufficient to explain its whole formation history.}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,open clusters and associations: general,star: early-type,stars: formation,stars: pre-main-sequence}, annotation = {ADS Bibcode: 2021MNRAS.508.1033S}}
@article{schilbach_origin_2008, title = {On the Origin of Field {{O-type}} Stars}, author = {Schilbach, E. and R{\"o}ser, S.}, year = {2008}, month = oct, journal = {Astronomy \& Astrophysics}, volume = {489}, number = {1}, pages = {105--114}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361:200809936}, urldate = {2019-09-06}, abstract = {\emph{Aims. {$<$}i/{$>$}We aim to identify the origins of field O-stars in the nearest 2 to 3 kpc around the Sun using the best presently available kinematic data on O-stars and on young open clusters. We investigate the question of whether the present-day data are consistent with the assumption that O-stars have formed in groups (clusters, associations), or in isolation.\emph{Methods. {$<$}i/{$>$}We apply the epicycle theory to back-trace the orbits of O-type stars and of candidate parent open clusters.\emph{Results. {$<$}i/{$>$}From the 370 O-stars in the ``Galactic O star catalog v 2.0'' (GOSV2) we have investigated 93 stars classified as \emph{field{$<$}i/{$>$}, and found the origin for 73 of them in 48 open clusters younger than 30 Myr. Only for 32 stars or about 9\% of all O-stars from this catalogue is the question of their origin in groups not solved; some of them may have originated in isolation or may have disintegrated the group in which they formed. Fifty percent of the young open clusters (age {$<$} 30 Myr) in the ``Catalogue of Open Cluster Data'' (COCD) have O-stars as members, or have ejected at least one O-star in the first 10 Myr of their life, or both. During this period the average mass loss from open clusters by ejecting O-stars is found to be 3 to 5 per Myr. We prove that \emph{{$\zeta<$}i/{$>$} Pup had its origin in the open cluster Trumpler 10 which it left about 2.5 Myr ago, and that its present-day distance is 300 pc (compared to 440 pc before). The revised distance implies a significant revision of the stellar parameters (a radius of 14 , a mass of 22.5 , and a luminosity of log of 5.74) i.e., \emph{{$\zeta<$}i/{$>$} Pup is closer, less massive, and less luminous than previously thought. Our findings provide independent estimates of the present-day distances and absolute magnitudes of field O-stars.}}}}}}}, copyright = {\textcopyright{} ESO, 2008}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\WVQL2CNM\\Schilbach and Röser - 2008 - On the origin of field O-type stars.pdf;C\:\\Users\\Emily\\Zotero\\storage\\ZDZL3JRV\\article.html}}
@article{schmeja_global_2014, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{III}}. 139 New Open Clusters at High {{Galactic}} Latitudes}, author = {Schmeja, S. and Kharchenko, N. V. and Piskunov, A. E. and R{\"o}ser, S. and Schilbach, E. and Froebrich, D. and Scholz, R.-D.}, year = {2014}, month = aug, journal = {Astronomy \& Astrophysics}, volume = {568}, pages = {A51}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201322720}, urldate = {2019-09-03}, abstract = {\emph{Context. {$<$}i/{$>$}An earlier analysis of the Milky Way Star Cluster (MWSC) catalogue revealed an apparent lack of old (\emph{t{$<$}i/{$>$} {$\greaterequivlnt$} 1 Gyr) open clusters in the solar neighbourhood (\emph{d{$<$}i/{$>$} {$\lessequivlnt$} 1 kpc).\emph{Aims. {$<$}i/{$>$}To fill this gap we undertook a search for hitherto unknown star clusters, assuming that the missing old clusters reside at high Galactic latitudes | \emph{b{$<$}i/{$>$} | {$>$} 20\textdegree.\emph{Methods. {$<$}i/{$>$}We were looking for stellar density enhancements using a star count algorithm on the 2MASS point source catalogue. To increase the contrast between potential clusters and the field, we applied filters in colour\textendash magnitude space according to typical colour\textendash magnitude diagrams of nearby old open clusters. The subsequent comparison with lists of known objects allowed us to select thus far unknown cluster candidates. For verification they were processed with the standard pipeline used within the MWSC survey for computing cluster membership probabilities and for determining structural, kinematic, and astrophysical parameters.\emph{Results. {$<$}i/{$>$}In total we discovered 782 density enhancements, 524 of which were classified as real objects. Among them 139 are new open clusters with ages 8.3 {$<$} log (\emph{t{$<$}i/{$>$} [ yr ] ) {$<$} 9.7, distances \emph{d{$<$}i/{$><$} 3 kpc, and distances from the Galactic plane 0.3 {$<$}\emph{Z{$<$}i/{$><$} 1 kpc. This new sample has increased the total number of known high latitude open clusters by about 150\%. Nevertheless, we still observe a lack of older nearby clusters up to 1 kpc from the Sun. This volume is expected to still contain about 60 unknown clusters that probably escaped our detection algorithm, which fails to detect sparse overdensities with large angular size.}}}}}}}}}}}, copyright = {\textcopyright{} ESO, 2014}, langid = {english}, keywords = {Catalogue: MWSC,OC Finder,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NXSQUGEX\\Schmeja et al. - 2014 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\M877Q2XI\\aa22720-13.html}}
@article{scholz_global_2015, title = {Global Survey of Star Clusters in the {{Milky Way}} - {{IV}}. 63 New Open Clusters Detected by Proper Motions}, author = {Scholz, R.-D. and Kharchenko, N. V. and Piskunov, A. E. and R{\"o}ser, S. and Schilbach, E.}, year = {2015}, month = sep, journal = {Astronomy \& Astrophysics}, volume = {581}, pages = {A39}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201526312}, urldate = {2019-09-03}, abstract = {\emph{Context. {$<$}i/{$>$}The global Milky Way Star Clusters (MWSC) survey provided new cluster membership lists and mean cluster parameters for nearly 80\% of all previously known Galactic clusters. The MWSC data reduction pipeline involved the catalogue of positions and proper motions (PPMXL) on the International Celestial Reference System (ICRS) and near-infrared photometry from the Two Micron All Sky Survey (2MASS). \emph{Aims. {$<$}i/{$>$}In the first extension to the MWSC, photometric filters were applied to the 2MASS catalogue to find new cluster candidates that were subsequently confirmed or rejected by the MWSC pipeline. To further extend the MWSC census, particularly of nearby clusters, we aimed at discovering new clusters by conducting an almost global search in proper motion catalogues as a starting point. \emph{Methods. {$<$}i/{$>$}We first selected high-quality samples from the PPMXL and the Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4) for comparison and verification of the proper motions. For 441 circular proper motion bins (radius 15 mas/yr) within {$\pm$}50 mas/yr, the sky outside a thin Galactic plane zone (| \emph{b{$<$}i/{$>$} | {$<$} 5\textdegree ) was binned in small areas (``sky pixels'') of 0.25 \texttimes{} 0.25 deg\textsuperscript{2{$<$}sup/{$>$}. Sky pixels with enhanced numbers of stars with a certain common proper motion in both catalogues were considered as cluster candidates. After visual inspection of the sky images, we built an automated procedure that combined these representations of the sky for neighbouring proper motion subsamples after a background correction. The 692 compact cluster candidates detected above a threshold that was equivalent to a minimum of 12 to 130 cluster stars in dependence on the Galactic latitude were then cross-checked with known star clusters and clusters of galaxies. New candidates served as input for the MWSC pipeline. \emph{Results. {$<$}i/{$>$}About half of our candidates overlapped with known clusters (46 globular and 68 open clusters in the Galaxy, about 150 known clusters of galaxies) or the Magellanic Clouds. About 10\% of our candidates are 63 new open clusters confirmed by the MWSC pipeline. They predominantly occupy the two inner Galactic quadrants and have apparent sizes and numbers of highly probable members slightly larger than those of the typically small MWSC clusters, whereas their other parameters (ages, distances, tidal radii) fall in the typical ranges. As we searched for compact clusters, we did not find new very nearby (extended) clusters, and the mean total proper motion of the new 63 clusters is with 6.3 mas/yr similar to the MWSC average (5.5 mas/yr). Only four new clusters have mean proper motions between 10 mas/yr and our observed maximum of about 13 mas/yr.}}}}}}}, copyright = {\textcopyright{} ESO, 2015}, langid = {english}, keywords = {Catalogue: MWSC,OC Finder,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\KR4EALCQ\\Scholz et al. - 2015 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\LFHYXWJH\\Scholz et al. - 2015 - Global survey of star clusters in the Milky Way - .pdf;C\:\\Users\\Emily\\Zotero\\storage\\5SMU6YN7\\aa26312-15.html}}
@article{scikit-learn, title = {Scikit-Learn: {{Machine}} Learning in {{Python}}}, author = {Pedregosa, F. and Varoquaux, G. and Gramfort, A. and Michel, V. and Thirion, B. and Grisel, O. and Blondel, M. and Prettenhofer, P. and Weiss, R. and Dubourg, V. and Vanderplas, J. and Passos, A. and Cournapeau, D. and Brucher, M. and Perrot, M. and Duchesnay, E.}, year = {2011}, journal = {Journal of Machine Learning Research}, volume = {12}, pages = {2825--2830}}
@article{semenova_gaia-eso_2020, title = {The {{Gaia-ESO}} Survey: {{3D NLTE}} Abundances in the Open Cluster {{NGC}} 2420 Suggest Atomic Diffusion and Turbulent Mixing at the Origin of Chemical Abundance Variations}, shorttitle = {The {{Gaia-ESO}} Survey}, author = {Semenova, Ekaterina and Bergemann, Maria and Deal, Morgan and Serenelli, Aldo and Hansen, Camilla Juul and Gallagher, Andrew and Bayo, Amelia and Bensby, Thomas and Bragaglia, Angela and Carraro, Giovanni and Morbidelli, Lorenzo and Pancino, Elena and Smiljanic, Rodolfo}, year = {2020}, month = oct, journal = {arXiv:2007.09153 [astro-ph]}, eprint = {2007.09153}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {Atomic diffusion and mixing processes in stellar interiors influence the structure and the surface composition of stars. Some of these processes cannot yet be modelled from the first principles. This limits their applicability in stellar models used for studies of stellar populations and Galactic evolution. Our main goal is to put constrains on the stellar structure and evolution models using new refined measurements of chemical composition in stars of Galactic open cluster. We use medium-resolution, 19 200 {$<$}= R {$<$}= 21 500, optical spectra of the stars in the open cluster NGC 2420 obtained within the Gaia-ESO survey. The sample covers all evolutionary stages from the main-sequence to red giant branch. Stellar parameters are derived using a combined Bayesian analysis of spectra, 2MASS photometry, and astrometric data from Gaia DR2. The abundances of Mg, Ca, Fe, and Li are determined from non-local thermodynamic equilibrium (NLTE) synthetic spectra, computed using one-dimensional (1D) and averaged three-dimensional (3D) model atmospheres. We compare our results with a grid of Code d'Evolution Stellaire Adaptatif et Modulaire (CESTAM) stellar evolution models, which include atomic diffusion, turbulent and rotational mixing. We find prominent evolutionary trends in the abundances of Fe, Ca, Mg, and Li with the mass of the stars in the cluster. Fe, Mg, and Ca show a depletion at the cluster turn-off, but the abundances gradually increase and flatten near the base of the RGB. The abundance trend for Li displays a signature of rotational mixing on the main-sequence and abrupt depletion on the subgiant branch, which is caused by advection of Li-poor material to the surface. The analysis of abundances combined with the CESTAM model predictions allows us to place limits on the parameter space of the models and to constrain the zone in the stellar interior where turbulent mixing takes place.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\KVHDC7PK\\2007.html}}
@article{shah_multi-wavelength_2020, title = {A Multi-Wavelength View of the Open Cluster {{NGC}} 2527: {{Discovery}} of Active Stars}, shorttitle = {A Multi-Wavelength View of the Open Cluster {{NGC}} 2527}, author = {Shah, Nevil and Singh, K. P. and Subramaniam, Annapurni}, year = {2020}, month = feb, journal = {arXiv:2002.12574 [astro-ph]}, eprint = {2002.12574}, primaryclass = {astro-ph}, urldate = {2020-03-02}, abstract = {Star clusters are ideal platforms for categorising X-ray emitting stars and to study X-ray emission as a function of stellar age and activity. We present a comprehensive study of an open star cluster, NGC2527, by combining data from XMM-UVOT-Gaia. Cluster membership of stars and their photometry are taken from Gaia and cross-matched with XMM and UVOT detections. We estimate the age of NGC2527 as \textasciitilde 630 Myr, reddening as E(B-V)=0.13 mag, and a distance of 642+/-30 pc using PARSEC isochrones. We detect 5 sub-subgiants and 5 bandgap stars, which defy single star evolution. We estimate the temperature, mass, radius, and luminosity of 53 single stars and 10 potential binary stars using a python code which fits single and composite Kurucz spectra to broad-band Spectral Energy Distribution. Among the 12 X-ray emitting members, we find 5 are potential RS CVn type binaries, 2 are potential FK Comae type of RGB stars, and 5 are main sequence (MS) stars with high coronal activity. Members with strong UV emission comprise of 1 RGB star, and several MS stars with UV excess suggestive of chromospheric activity. Based on comparison with other clusters, we tentatively suggest that X-ray luminosity of both RS CVn and contact binaries increases with age suggesting more active binaries are present in older clusters as compared to younger clusters. This study suggests the possible presence of W UMa and FK Comae type stars in younger (age\textasciitilde 630 Myr) clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{shull_gaia-edr3_2021, title = {Gaia-{{EDR3 Parallax Distances}} to the {{Great Carina Nebula}} and Its {{Star Clusters}} ({{Trumpler}} 14, 15, 16)}, author = {Shull, Michael and Darling, Jeremy and Danforth, Charles}, year = {2021}, month = mar, journal = {arXiv:2103.07922 [astro-ph]}, eprint = {2103.07922}, primaryclass = {astro-ph}, urldate = {2021-03-17}, abstract = {Using offset-corrected Gaia-EDR3 parallax measurements and spectrophotometric methods, we have determined distances for 69 massive stars in the Carina OB1 association and associated clusters: Trumpler 16 (21 stars), Trumpler 14 (20 stars), Trumpler 15 (3 stars), Bochum 11 (5 stars), and South Pillars region (20 stars). Past distance estimates to the Carina Nebula range from 2.2 to 3.6 kpc, with uncertainties arising from photometry and anomalous dust extinction. The EDR3 parallax solutions show considerable improvement over DR2, with typical errors \$\textbackslash sigma\_\{\textbackslash varpi\}/\textbackslash varpi \textbackslash approx\$\textasciitilde 3-5\%. The O-type stars in the Great Carina Nebula lie at essentially the same distance (\$2.35\textbackslash pm0.08\$ kpc), quoting mean and rms variance. The clusters have distances of \$2.32\textbackslash pm0.12\$ kpc (Tr 16), \$2.37\textbackslash pm0.15\$ kpc (Tr 14), \$2.36\textbackslash pm0.09\$ kpc (Tr 15), and \$2.33\textbackslash pm0.12\$ kpc (Bochum 11) in good agreement with the \$\textbackslash eta\$ Car distance of around 2.3 kpc. O-star proper motions suggest internal (2D) velocity dispersions \$\textbackslash sim4\$ km/s for Tr 14 and Tr 16. Reliable distances allow estimates of cluster sizes, stellar dynamics, luminosities, and fluxes of photoionizing radiation incident on photodissociation regions in the region. We estimate that Tr 14 and Tr 16 have half-mass radii \$r\_h = 1.5-1.8\$ pc, stellar crossing times \$t\_\{\textbackslash rm cr\} = r\_h/v\_m \textbackslash approx 0.7-0.8\$ Myr, and two-body relaxation times \$t\_\{rh\} \textbackslash approx 40-80\$ Myr. The underlying velocity dispersion for Tr 14, if a bound cluster, would be \$v\_m \textbackslash approx 2.1\^\{+0.7\}\_\{-0.4\}\$ km/s for \$N = 7600\^\{+5800\}\_\{-2600\}\$ stars. With the higher dispersions of the O-stars, mass segregation might occur slowly, on times scales of 3-6\textasciitilde Myr.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\9GMHBGZV\\2103.html}}
@article{sim_207_2019, title = {207 {{New Open Star Clusters}} within 1 Kpc from {{Gaia Data Release}} 2}, author = {Sim, Gyuheon and Lee, Sang Hyun and Ann, Hong Bae and Kim, Seunghyeon}, year = {2019}, month = oct, journal = {Journal of the Korean Astronomical Society}, volume = {52}, eprint = {1907.06872}, pages = {145--158}, urldate = {2019-10-25}, abstract = {We conducted a survey of open clusters within 1 kpc from the Sun using the astrometric and photometric data of the Gaia Data Release 2. We found 655 cluster candidates by visual inspection of the stellar distributions in proper motion space and spatial distributions in l-b space. All of the 655 cluster candidates have a well defined main-sequence except for two candidates if we consider that the main sequence of very young clusters is somewhat broad due to differential extinction. Cross-matching of our 653 open clusters with known open clusters in various catalogs resulted in 207 new open clusters. We present the physical properties of the newly discovered open clusters. The majority of the newly discovered open clusters are of young to intermediate age and have less than \textasciitilde 50 member stars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{skrutskie_two_2006, title = {The {{Two Micron All Sky Survey}} ({{2MASS}})}, author = {Skrutskie, M. F. and Cutri, R. M. and Stiening, R. and Weinberg, M. D. and Schneider, S. and Carpenter, J. M. and Beichman, C. and Capps, R. and Chester, T. and Elias, J. and Huchra, J. and Liebert, J. and Lonsdale, C. and Monet, D. G. and Price, S. and Seitzer, P. and Jarrett, T. and Kirkpatrick, J. D. and Gizis, J. E. and Howard, E. and Evans, T. and Fowler, J. and Fullmer, L. and Hurt, R. and Light, R. and Kopan, E. L. and Marsh, K. A. and McCallon, H. L. and Tam, R. and Van Dyk, S. and Wheelock, S.}, year = {2006}, month = feb, journal = {The Astronomical Journal}, volume = {131}, pages = {1163--1183}, issn = {0004-6256}, doi = {10.1086/498708}, urldate = {2022-12-06}, abstract = {Between 1997 June and 2001 February the Two Micron All Sky Survey (2MASS) collected 25.4 Tbytes of raw imaging data covering 99.998\% of the celestial sphere in the near-infrared J (1.25 {$\mu$}m), H (1.65 {$\mu$}m), and Ks (2.16 {$\mu$}m) bandpasses. Observations were conducted from two dedicated 1.3 m diameter telescopes located at Mount Hopkins, Arizona, and Cerro Tololo, Chile. The 7.8 s of integration time accumulated for each point on the sky and strict quality control yielded a 10 {$\sigma$} point-source detection level of better than 15.8, 15.1, and 14.3 mag at the J, H, and Ks bands, respectively, for virtually the entire sky. Bright source extractions have 1 {$\sigma$} photometric uncertainty of {$<$}0.03 mag and astrometric accuracy of order 100 mas. Calibration offsets between any two points in the sky are {$<$}0.02 mag. The 2MASS All-Sky Data Release includes 4.1 million compressed FITS images covering the entire sky, 471 million source extractions in a Point Source Catalog, and 1.6 million objects identified as extended in an Extended Source Catalog.}, keywords = {Catalogs,Infrared: General,Surveys}, annotation = {ADS Bibcode: 2006AJ....131.1163S}}
@article{smith_ngts_2021, title = {{{NGTS}} Clusters Survey -- {{III}}: {{A}} Low-Mass Eclipsing Binary in the {{Blanco}} 1 Open Cluster Spanning the Fully Convective Boundary}, shorttitle = {{{NGTS}} Clusters Survey -- {{III}}}, author = {Smith, Gareth D. and Gillen, Edward and Queloz, Didier and Hillenbrand, Lynne A. and Acton, Jack S. and Alves, Douglas R. and Anderson, David R. and Bayliss, Daniel and Briegal, Joshua T. and Burleigh, Matthew R. and Casewell, Sarah L. and Delrez, Laetitia and Dransfield, Georgina and Ducrot, Elsa and Gill, Samuel and Gillon, Micha{\"e}l and Goad, Michael R. and G{\"u}nther, Maximilian N. and Henderson, Beth A. and Jenkins, James S. and Jehin, Emmanu{\"e}l and Moyano, Maximiliano and Murray, Catriona A. and Pedersen, Peter P. and Sebastian, Daniel and Thompson, Samantha and Tilbrook, Rosanna H. and Triaud, Amaury H. M. J. and Vines, Jose I. and Wheatley, Peter J.}, year = {2021}, month = sep, journal = {arXiv:2109.00836 [astro-ph]}, eprint = {2109.00836}, primaryclass = {astro-ph}, urldate = {2021-09-15}, abstract = {We present the discovery and characterisation of an eclipsing binary identified by the Next Generation Transit Survey in the \$\textbackslash sim\$115 Myr old Blanco 1 open cluster. NGTS J0002-29 comprises three M dwarfs: a short-period binary and a companion in a wider orbit. This system is the first well-characterised, low-mass eclipsing binary in Blanco 1. With a low mass ratio, a tertiary companion and binary components that straddle the fully convective boundary, it is an important benchmark system, and one of only two well-characterised, low-mass eclipsing binaries at this age. We simultaneously model light curves from NGTS, TESS, SPECULOOS and SAAO, radial velocities from VLT/UVES and Keck/HIRES, and the system's spectral energy distribution. We find that the binary components travel on circular orbits around their common centre of mass in \$P\_\{\textbackslash rm orb\} = 1.09800524 \textbackslash pm 0.00000038\$ days, and have masses \$M\_\{\textbackslash rm pri\}=0.3978\textbackslash pm 0.0033\$ M\$\_\{\textbackslash odot\}\$ and \$M\_\{\textbackslash rm sec\}=0.2245\textbackslash pm 0.0018\$ M\$\_\{\textbackslash odot\}\$, radii \$R\_\{\textbackslash rm pri\}=0.4037\textbackslash pm 0.0048\$ R\$\_\{\textbackslash odot\}\$ and \$R\_\{\textbackslash rm sec\}=0.2759\textbackslash pm 0.0055\$ R\$\_\{\textbackslash odot\}\$, and effective temperatures \$T\_\{\textbackslash rm pri\}=3372\textbackslash,\^\{+44\}\_\{-37\}\$ K and \$T\_\{\textbackslash rm sec\}=3231\textbackslash,\^\{+38\}\_\{-31\}\$ K. We compare these properties to the predictions of seven stellar evolution models, which typically imply an inflated primary. The system joins a list of 19 well-characterised, low-mass, sub-Gyr, stellar-mass eclipsing binaries, which constitute some of the strongest observational tests of stellar evolution theory at low masses and young ages.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\4SPGW7S2\\2109.html}}
@article{soubiran_open_2018, title = {Open Cluster Kinematics with {{Gaia DR2}}}, author = {Soubiran, C. and {Cantat-Gaudin}, T. and {Romero-G{\'o}mez}, M. and Casamiquela, L. and Jordi, C. and Vallenari, A. and Antoja, T. and {Balaguer-N{\'u}{\~n}ez}, L. and Bossini, D. and Bragaglia, A. and Carrera, R. and {Castro-Ginard}, A. and Figueras, F. and Heiter, U. and Katz, D. and {Krone-Martins}, A. and Campion, J.-F. Le and Moitinho, A. and Sordo, R.}, year = {2018}, month = nov, journal = {Astronomy \& Astrophysics}, volume = {619}, pages = {A155}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201834020}, urldate = {2019-09-06}, abstract = {\emph{Context{$<$}i/{$>$}. Open clusters are very good tracers of the evolution of the Galactic disc. Thanks to \emph{Gaia{$<$}i/{$>$}, their kinematics can be investigated with an unprecedented precision and accuracy.\emph{Aims{$<$}i/{$>$}. The distribution of open clusters in the 6D phase space is revisited with \emph{Gaia{$<$}i/{$>$} DR2.\emph{Methods{$<$}i/{$>$}. The weighted mean radial velocity of open clusters was determined, using the most probable members available from a previous astrometric investigation that also provided mean parallaxes and proper motions. Those parameters, all derived from \emph{Gaia{$<$}i/{$>$} DR2 only, were combined to provide the 6D phase-space information of 861 clusters. The velocity distribution of nearby clusters was investigated, as well as the spatial and velocity distributions of the whole sample as a function of age. A high-quality subsample was used to investigate some possible pairs and groups of clusters sharing the same Galactic position and velocity.\emph{Results{$<$}i/{$>$}. For the high-quality sample of 406 clusters, the median uncertainty of the weighted mean radial velocity is 0.5 km s\textsuperscript{-1{$<$}sup/{$>$}. The accuracy, assessed by comparison to ground-based high-resolution spectroscopy, is better than 1 km s\textsuperscript{-1{$<$}sup/{$>$}. Open clusters nicely follow the velocity distribution of field stars in the close solar neighbourhood as previously revealed by \emph{Gaia{$<$}i/{$>$} DR2. As expected, the vertical distribution of young clusters is very flat, but the novelty is the high precision to which this can be seen. The dispersion of vertical velocities of young clusters is at the level of 5 km s\textsuperscript{-1{$<$}sup/{$>$}. Clusters older than 1 Gyr span distances to the Galactic plane of up to 1 kpc with a vertical velocity dispersion of 14 km s\textsuperscript{-1{$<$}sup/{$>$}, typical of the thin disc. Five pairs of clusters and one group with five members might be physically related. Other binary candidates that have been identified previously are found to be chance alignments.}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\SDL844RS\\Soubiran et al. - 2018 - Open cluster kinematics with Gaia DR2.pdf;C\:\\Users\\Emily\\Zotero\\storage\\LMPNFI3U\\aa34020-18.html}}
@article{souza_self-consistent_2020, title = {Self-Consistent Analysis of Stellar Clusters: {{An}} Application to {{HST}} Data of the Halo Globular Cluster {{NGC}} 6752}, shorttitle = {Self-Consistent Analysis of Stellar Clusters}, author = {Souza, Stefano O. and Kerber, Leandro O. and Barbuy, Beatriz and {P{\'e}rez-Villegas}, Angeles and Oliveira, Raphael A. P. and Nardiello, Domenico}, year = {2020}, month = jan, journal = {arXiv:2001.02697 [astro-ph]}, eprint = {2001.02697}, primaryclass = {astro-ph}, urldate = {2020-01-10}, abstract = {The Bayesian isochrone fitting using the Markov chain Monte Carlo algorithm is applied, to derive the probability distribution of the parameters age, metallicity, reddening, and absolute distance modulus. We introduce the \textbackslash texttt\{SIRIUS\} code by means of simulated color-magnitude diagrams, including the analysis of multiple stellar populations. The population tagging is applied from the red giant branch to the bottom of the main sequence. Through sanity checks using synthetic \{\textbackslash it HST\} color-magnitude diagrams of globular clusters we verify the code reliability in the context of simple and multiple stellar populations. In such tests, the formal uncertainties in age or age difference, metallicity, reddening, and absolute distance modulus can reach \$400\$ Myr, \$0.03\$ dex, \$0.01\$ mag, and \$0.03\$ mag, respectively. We apply the method to analyse NGC 6752, using Dartmouth stellar evolutionary models. Assuming a single stellar population, we derive an age of \$13.7\textbackslash pm0.5\$ Gyr and a distance of \$d\_\{\textbackslash odot\}=4.11\textbackslash pm 0.08\$ kpc, with the latter in agreement within \$\textasciitilde 3\textbackslash sigma\$ with the inverse Gaia parallax. In the analysis of the multiple stellar populations, three \{populations\} are clearly identified. From the Chromosome Map and UV/Optical two-color diagrams inspection, we found a fraction of stars of \$25\textbackslash pm5\$, \$46\textbackslash pm7\$, and \$29\textbackslash pm5\$ per cent, for the first, second, and third generations, respectively. These fractions are in good agreement with the literature. An age difference of \$500\textbackslash pm410\$ Myr between the first and the third generation is found, with the uncertainty decreasing to \$400\$ Myr when the helium enhancement is taken into account.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NEKLH8KT\\2001.html}}
@article{speagle_dynesty:_2019, title = {Dynesty: {{A Dynamic Nested Sampling Package}} for {{Estimating Bayesian Posteriors}} and {{Evidences}}}, shorttitle = {Dynesty}, author = {Speagle, Joshua S.}, year = {2019}, month = apr, journal = {arXiv:1904.02180 [astro-ph, stat]}, eprint = {1904.02180}, primaryclass = {astro-ph, stat}, urldate = {2019-10-02}, abstract = {We present dynesty, a public, open-source, Python package to estimate Bayesian posteriors and evidences (marginal likelihoods) using Dynamic Nested Sampling. By adaptively allocating samples based on posterior structure, Dynamic Nested Sampling has the benefits of Markov Chain Monte Carlo algorithms that focus exclusively on posterior estimation while retaining Nested Sampling's ability to estimate evidences and sample from complex, multi-modal distributions. We provide an overview of Nested Sampling, its extension to Dynamic Nested Sampling, the algorithmic challenges involved, and the various approaches taken to solve them. We then examine dynesty's performance on a variety of toy problems along with several astronomical applications. We find in particular problems dynesty can provide substantial improvements in sampling efficiency compared to popular MCMC approaches in the astronomical literature. More detailed statistical results related to Nested Sampling are also included in the Appendix.}, archiveprefix = {arxiv}, langid = {english}, keywords = {Astrophysics - Instrumentation and Methods for Astrophysics,Statistics - Computation}, file = {C\:\\Users\\Emily\\Zotero\\storage\\9C64DIGE\\Speagle_2019_dynesty.pdf}}
@article{spina_gaia-eso_2022, title = {The {{Gaia-ESO Survey}}: {{Chemical}} Tagging in the Thin Disk. {{Open}} Clusters Blindly Recovered in the Elemental Abundance Space}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {Spina, L. and Magrini, L. and Sacco, G. G. and Casali, G. and Vallenari, A. and Tautvaisien{\.e}, G. and {Jim{\'e}nez-Esteban}, F. and Gilmore, G. and Randich, S. and Feltzing, S. and Jeffries, R. D. and Bensby, T. and Bragaglia, A. and Smiljanic, R. and Carraro, G. and Morbidelli, L. and Zaggia, S.}, year = {2022}, month = mar, journal = {arXiv:2203.14991 [astro-ph]}, eprint = {2203.14991}, primaryclass = {astro-ph}, urldate = {2022-03-30}, abstract = {The chemical makeup of a star provides the fossil information of the environment where it formed. Under this premise, it should be possible to use chemical abundances to tag stars that formed within the same stellar association. This idea - known as chemical tagging - has not produced the expected results, especially within the thin disk where open stellar clusters have chemical patterns that are difficult to disentangle. The ultimate goal of this study is to probe the feasibility of chemical tagging within the thin disk population using high-quality data from a controlled sample of stars. We also aim at improving the existing techniques of chemical tagging and giving guidance on different strategies of clustering analysis in the elemental abundance space. Here we develop the first blind search of open clusters' members through clustering analysis in the elemental abundance space using the OPTICS algorithm applied to data from the Gaia-ESO survey. First, we evaluate different strategies of analysis, determining which ones are more performing. Second, we apply these methods to a data set including both field stars and open clusters attempting a blind recover of as many open clusters as possible. We show how specific strategies of data analysis can improve the final results. Specifically, we demonstrate that open clusters can be more efficaciously recovered with the Manhattan metric and on a space whose dimensions are carefully selected. Using these (and other) prescriptions we are able to recover open clusters hidden in our data set and find new members of these stellar associations. Our results indicate that there are chances of recovering open clusters' members via clustering analysis in the elemental abundance space. Presumably, the performances of chemical tagging will further increase with higher quality data and more sophisticated clustering algorithms.}, archiveprefix = {arxiv}, keywords = {85-02,Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics,Astrophysics - Solar and Stellar Astrophysics}}
@article{spina_galah_2020, title = {The {{GALAH}} Survey: Tracing the {{Galactic}} Disk with {{Open Clusters}}}, shorttitle = {The {{GALAH}} Survey}, author = {Spina, Lorenzo and Ting, Yuan-Sen and De Silva, Gayandhi M. and Frankel, Neige and Sharma, Sanjib and {Cantat-Gaudin}, Tristan and Joyce, Meridith and Stello, Dennis and Karakas, Amanda I. and Asplund, Martin B. and Nordlander, Thomas and Casagrande, Luca and D'Orazi, Valentina and Casey, Andrew R. and Cottrell, Peter and {Tepper-Garc{\'i}a}, Thor and Baratella, Martina and Kos, Janez and {\v C}otar, Klemen and {Bland-Hawthorn}, Joss and Buder, Sven and Freeman, Ken C. and Hayden, Michael R. and Lewis, Geraint F. and Lin, Jane and Lind, Karin and Martell, Sarah L. and Schlesinger, Katharine J. and Simpson, Jeffrey D. and Zucker, Daniel B. and Zwitter, Toma{\v z}}, year = {2020}, month = nov, journal = {arXiv:2011.02533 [astro-ph]}, eprint = {2011.02533}, primaryclass = {astro-ph}, urldate = {2020-11-30}, abstract = {Open clusters are unique tracers of the history of our own Galaxy's disk. According to our membership analysis based on \textbackslash textit\{Gaia\} astrometry, out of the 226 potential clusters falling in the footprint of GALAH or APOGEE, we find that 205 have secure members that were observed by at least one of the survey. Furthermore, members of 134 clusters have high-quality spectroscopic data that we use to determine their chemical composition. We leverage this information to study the chemical distribution throughout the Galactic disk of 21 elements, from C to Eu, and including Fe. The radial metallicity gradient obtained from our analysis is \$-\$0.076\$\textbackslash pm\$0.009 dex kpc\$\^\{-1\}\$, which is in agreement with previous works based on smaller samples. Furthermore, the gradient in the [Fe/H] - guiding radius (r\$\_\{\textbackslash rm guid\}\$) plane is \$-\$0.073\$\textbackslash pm\$0.008 dex kpc\$\^\{-1\}\$. We also reveal trends in the [X/Fe] - r\$\_\{\textbackslash rm guid\}\$ - age space, which are important to understand production rates of different elements as a function of space and time. Finally, we observe subtle - but significant - differences on how field stars and open clusters trace the distribution of chemical elements throughout the Galactic disk. As it is discussed in the paper, these differences are probably due to the physical selection effect imposed by our Galaxy, which preserves the clusters living far from its gravitational potential perturbations (e.g., spirals, bars, molecular clouds), while it destroys all the others.}, archiveprefix = {arxiv}, keywords = {85-02,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\DGWLLARL\\2011.html}}
@article{spina_mapping_2022, title = {Mapping the {{Galactic Metallicity Gradient}} with {{Open Clusters}}: {{The State-of-the-Art}} and {{Future Challenges}}}, shorttitle = {Mapping the {{Galactic Metallicity Gradient}} with {{Open Clusters}}}, author = {Spina, Lorenzo and Magrini, Laura and Cunha, Katia}, year = {2022}, month = jan, journal = {Universe}, volume = {8}, number = {2}, eprint = {2202.00463}, pages = {87}, issn = {2218-1997}, doi = {10.3390/universe8020087}, urldate = {2022-02-02}, abstract = {In this paper, we make use of data collected for open cluster members by high-resolution spectroscopic surveys and programmes (i.e., APOGEE, Gaia-ESO, GALAH, OCCASO, and SPA). These data have been homogenised and then analysed as a whole. The resulting catalogue contains [Fe/H] and orbital parameters for 251 Galactic open clusters. The slope of the radial metallicity gradient obtained through 175 open clusters with high-quality metallicity determinations is \$-\$0.064 \$\textbackslash pm\$ 0.007 dex kpc\$\^\{-1\}\$. The radial metallicity distribution traced by open clusters flattens beyond R\$\_\{\textbackslash rm Gal\}\$=12.1 \$\textbackslash pm\$ 1.1 kpc. The slope traced by open clusters in the [Fe/H]-L\$\_\{\textbackslash rm z\}\$ diagram is \$-\$0.31 \$\textbackslash pm\$ 0.02 10\$\^\{3\}\$ dex km\$\^\{-1\}\$ kpc\$\^\{-1\}\$ s, but it flattens beyond L\$\_\{\textbackslash rm z\}\$=2769 \$\textbackslash pm\$ 177 km kpc s\$\^\{-1\}\$. In this paper, we also review some high-priority practical challenges around the study of open clusters that will significantly push our understanding beyond the state-of-the-art. Finally, we compare the shape of the galactic radial metallicity gradient to those of other spiral galaxies.}, archiveprefix = {arxiv}, keywords = {85-02,Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\8MJRUWGF\\2202.html}}
@article{spindler_astrovader_2020, title = {{{AstroVaDEr}}: {{Astronomical Variational Deep Embedder}} for {{Unsupervised Morphological Classification}} of {{Galaxies}} and {{Synthetic Image Generation}}}, shorttitle = {{{AstroVaDEr}}}, author = {Spindler, Ashley and Geach, James E. and Smith, Michael J.}, year = {2020}, month = sep, journal = {arXiv:2009.08470 [astro-ph]}, eprint = {2009.08470}, primaryclass = {astro-ph}, urldate = {2020-10-07}, abstract = {We present AstroVaDEr, a variational autoencoder designed to perform unsupervised clustering and synthetic image generation using astronomical imaging catalogues. The model is a convolutional neural network that learns to embed images into a low dimensional latent space, and simultaneously optimises a Gaussian Mixture Model (GMM) on the embedded vectors to cluster the training data. By utilising variational inference, we are able to use the learned GMM as a statistical prior on the latent space to facilitate random sampling and generation of synthetic images. We demonstrate AstroVaDEr's capabilities by training it on gray-scaled \textbackslash textit\{gri\} images from the Sloan Digital Sky Survey, using a sample of galaxies that are classified by Galaxy Zoo 2. An unsupervised clustering model is found which separates galaxies based on learned morphological features such as axis ratio, surface brightness profile and orientation. We use the learned mixture model to generate synthetic images of galaxies based on the morphological profiles of the Gaussian components. AstroVaDEr demonstrates the ability to classify the morphology of galaxies in a human-interpretable way without the need for labelled training data. The network is scalable and flexible, allowing for larger datasets to be classified, or different kinds of imaging data. We also demonstrate the generative properties of the model, which allow for realistic synthetic images of galaxies to be sampled from the learned classification scheme. These can be used to create synthetic image catalogs or to perform image processing tasks such as deblending.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}}
@article{tarricq_3d_2020, title = {{{3D}} Kinematics and Age Distribution of the {{Open Cluster}} Population}, author = {Tarricq, Y. and Soubiran, C. and Casamiquela, L. and {Cantat-Gaudin}, T. and Chemin, L. and Anders, F. and Antoja, T. and {Romero-G{\'o}mez}, M. and Figueras, F. and Jordi, C. and Bragaglia, A. and {Balaguer-N{\'u}{\~n}ez}, L. and Carrera, R. and {Castro-Ginard}, A. and Moitinho, A. and Ramos, P. and Bossini, D.}, year = {2020}, month = dec, journal = {arXiv:2012.04017 [astro-ph]}, eprint = {2012.04017}, primaryclass = {astro-ph}, urldate = {2020-12-09}, abstract = {Open Clusters (OCs) can trace with a great accuracy the evolution of the Galactic disk. The aim of this work is to study the kinematical behavior of the OC population over time. We take advantage of the latest age determinations of OCs to investigate the correlations of the 6D phase space coordinates and orbital properties with age. We also investigate the rotation curve of the Milky Way traced by OCs and we compare it to that of other observational or theoretical studies. We gathered nearly 30000 Radial Velocity (RV) measurements of OC members from both Gaia-RVS data and ground based surveys and catalogues. We computed the weighted mean RV, Galactic velocities and orbital parameters of 1382 OCs. We investigated their distributions as a function of age, and by comparison to field stars. We provide the largest RV catalogue available for OCs, half of it based on at least 3 members. Compared to field stars, we note that OCs are not exactly on the same arches in the radial-azimuthal velocity plane, while they seem to follow the same diagonal ridges in the Galactic radial distribution of azimuthal velocities. Velocity ellipsoids in different age bins all show a clear anisotropy. The heating rate of the OC population is similar to that of field stars for the radial and azimuthal components but significantly lower for the vertical component. The rotation curve drawn by our sample of clusters shows several dips, which match the wiggles derived from non-axisymmetric models of the Galaxy. From the computation of orbits, we obtain a clear dependence of the maximum height and eccentricity with age. Finally, the orbital characteristics of the sample of clusters as shown by the action variables, follow the distribution of field stars. The additional age information of the clusters points towards some (weak) age dependence of the known moving groups.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}}
@article{tarricq_structural_2022, title = {Structural Parameters of 389 Local {{Open Clusters}}}, author = {Tarricq, Y. and Soubiran, C. and Casamiquela, L. and {Castro-Ginard}, A. and Olivares, J. and {Miret-Roig}, N. and Galli, P. A. B.}, year = {2022}, journal = {Astronomy \& Astrophysics}, volume = {659}, eprint = {2111.05291}, pages = {A59}, urldate = {2021-11-11}, abstract = {The distribution of member stars in the surroundings of an Open Cluster (OC) can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of OCs as a function of their age and position in the Galaxy brings constraints on theoretical models of cluster evolution. The Gaia catalogue is very appropriate to find members of OCs at large distance from their centers. We aim at revisiting the membership lists of OCs from the solar vicinity, in particular by extending these membership lists to the peripheral areas thanks to Gaia EDR3. We used the clustering algorithm HDBSCAN on Gaia parallaxes and proper motions to systematically look for members up to 50 pc from the cluster centers. We fitted a King's function on the radial density profile of these clusters and a Gaussian Mixture Model on their two dimensional distribution of members. We also evaluated the degree of mass segregation of the clusters. Our methodology performs well on 389 clusters out of the 467 selected ones. We report the detection of vast coronae around almost all the clusters and the detection of 71 OCs with tidal tails, multiplying by more than four the number of such structures identified. We find the size of the cores to be on average smaller for old clusters than for young ones. Also, the overall size of the clusters seems to slightly increase with age while the fraction of stars in the halo seems to decrease. As expected the mass segregation is more pronounced in the oldest clusters but a clear trend with age is not seen. OCs are more extended than previously expected, regardless of their age. The decrease in the proportion of stars populating the clusters halos highlights the different cluster evaporation processes and the short timescales they need to affect the clusters. Reported parameters all depend on cluster ages but can not be described as single functions of time.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\BH3JHV2V\\2111.html}}
@article{tian_discovery_2020, title = {Discovery of a Young Stellar "Snake" with Two Dissolving Cores in the Solar Neighborhood}, author = {Tian, Hai-Jun}, year = {2020}, month = sep, journal = {The Astrophysical Journal}, volume = {904}, number = {2}, eprint = {2005.12265}, pages = {196}, urldate = {2020-10-07}, abstract = {We report the discovery of a young (only 30-40\textbackslash,Myr) snake-like structure (dubbed a stellar "snake") in the solar neighborhood from \{\textbackslash it Gaia\} DR2. The average distance of this structure is about 310\textbackslash,pc from us. Both the length and width are over 200\textbackslash,pc, but the thickness is only about 80\textbackslash,pc. The "snake" has one tail and two dissolving cores, which can be clearly distinguished in the 6D phase space. The whole structure includes thousands of members with a total mass of larger than 2000\textbackslash,\$M\_\{\textbackslash odot\}\$ in an uniform population. The population is so young that it can not be well explained with the classical theory of tidal tails. We therefore suspect that the "snake" is hierarchically primordial, rather than the result of dynamically tidal stripping, even if the "snake" is probably expanding. The coherent 5D phase information and the ages suggest that the "snake" was probably born in the same environment as the filamentary structure of Beccari et al.(2020). If so, the "snake" could extend the sky region of the Vela OB2 association by a factor of \$\textbackslash sim 2\$, and supplement the census of its coeval structures. This finding is useful to understand the history of the formation and evolution of the Vela OB2 complex. The age of the "snake" well matches with that of the Gould Belt. In the sky region of our interest, we detect one new open cluster, which is named as Tian 1 in this work.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M92MMX3K\\2005.html}}
@article{torniamenti_dynamics_2022, title = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters: The Impact of Long-Term Star Cluster Evolution}, shorttitle = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters}, author = {Torniamenti, Stefano and Rastello, Sara and Mapelli, Michela and Di Carlo, Ugo N. and Ballone, Alessandro and Pasquato, Mario}, year = {2022}, month = mar, journal = {arXiv:2203.08163 [astro-ph]}, eprint = {2203.08163}, primaryclass = {astro-ph}, urldate = {2022-03-28}, abstract = {Dynamical interactions in dense star clusters are considered one of the most effective formation channels of binary black holes (BBHs). Here, we present direct \$N-\$body simulations of two different star cluster families: low-mass (\$\textbackslash sim\{500-800\}\$ M\$\_\textbackslash odot\$) and high-mass star clusters (\$\textbackslash ge\{5000\}\$ M\$\_\textbackslash odot\$). We show that the formation channels of BBHs in low- and high-mass star clusters are extremely different and lead to two completely distinct populations of BBH mergers. Low-mass clusters host mainly low-mass BBHs born from binary evolution, while BBHs in high-mass clusters are relatively massive (chirp mass up to \$\textbackslash sim\{50\}\$ M\$\_\textbackslash odot\$) and driven by dynamical exchanges. Tidal disruption dramatically quenches the formation and dynamical evolution of BBHs in low-mass clusters on a very short timescale (\$\textbackslash lesssim\{100\}\$ Myr), while BBHs in high-mass clusters undergo effective dynamical hardening until the end of our simulations (1.5 Gyr). In high-mass clusters we find 4\% of BBHs with primary mass in the pair-instability mass gap, all of them born via stellar collisions, while none of them forms in low-mass clusters. These differences are crucial for the interpretation of the formation channels of gravitational-wave sources.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{torniamenti_dynamics_2022-1, title = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters: The Impact of Long-Term Star Cluster Evolution}, shorttitle = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters}, author = {Torniamenti, Stefano and Rastello, Sara and Mapelli, Michela and Di Carlo, Ugo N. and Ballone, Alessandro and Pasquato, Mario}, year = {2022}, month = mar, journal = {arXiv:2203.08163 [astro-ph]}, eprint = {2203.08163}, primaryclass = {astro-ph}, urldate = {2022-03-24}, abstract = {Dynamical interactions in dense star clusters are considered one of the most effective formation channels of binary black holes (BBHs). Here, we present direct \$N-\$body simulations of two different star cluster families: low-mass (\$\textbackslash sim\{500-800\}\$ M\$\_\textbackslash odot\$) and high-mass star clusters (\$\textbackslash ge\{5000\}\$ M\$\_\textbackslash odot\$). We show that the formation channels of BBHs in low- and high-mass star clusters are extremely different and lead to two completely distinct populations of BBH mergers. Low-mass clusters host mainly low-mass BBHs born from binary evolution, while BBHs in high-mass clusters are relatively massive (chirp mass up to \$\textbackslash sim\{50\}\$ M\$\_\textbackslash odot\$) and driven by dynamical exchanges. Tidal disruption dramatically quenches the formation and dynamical evolution of BBHs in low-mass clusters on a very short timescale (\$\textbackslash lesssim\{100\}\$ Myr), while BBHs in high-mass clusters undergo effective dynamical hardening until the end of our simulations (1.5 Gyr). In high-mass clusters we find 4\% of BBHs with primary mass in the pair-instability mass gap, all of them born via stellar collisions, while none of them forms in low-mass clusters. These differences are crucial for the interpretation of the formation channels of gravitational-wave sources.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{torniamenti_dynamics_binary_2022, title = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters: The Impact of Long-Term Star Cluster Evolution}, shorttitle = {Dynamics of Binary Black Holes in Low and High-Mass Young Star Clusters}, author = {Torniamenti, Stefano and Rastello, Sara and Mapelli, Michela and Di Carlo, Ugo N. and Ballone, Alessandro and Pasquato, Mario}, year = {2022}, month = mar, journal = {arXiv:2203.08163 [astro-ph]}, eprint = {2203.08163}, primaryclass = {astro-ph}, urldate = {2022-03-17}, abstract = {Dynamical interactions in dense star clusters are considered one of the most effective formation channels of binary black holes (BBHs). Here, we present direct \$N-\$body simulations of two different star cluster families: low-mass (\$\textbackslash sim\{500-800\}\$ M\$\_\textbackslash odot\$) and high-mass star clusters (\$\textbackslash ge\{5000\}\$ M\$\_\textbackslash odot\$). We show that the formation channels of BBHs in low- and high-mass star clusters are extremely different and lead to two completely distinct populations of BBH mergers. Low-mass clusters host mainly low-mass BBHs born from binary evolution, while BBHs in high-mass clusters are relatively massive (chirp mass up to \$\textbackslash sim\{50\}\$ M\$\_\textbackslash odot\$) and driven by dynamical exchanges. Tidal disruption dramatically quenches the formation and dynamical evolution of BBHs in low-mass clusters on a very short timescale (\$\textbackslash lesssim\{100\}\$ Myr), while BBHs in high-mass clusters undergo effective dynamical hardening until the end of our simulations (1.5 Gyr). In high-mass clusters we find 4\% of BBHs with primary mass in the pair-instability mass gap, all of them born via stellar collisions, while none of them forms in low-mass clusters. These differences are crucial for the interpretation of the formation channels of gravitational-wave sources.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\5FAHTJQ8\\2203.html}}
@article{torniamenti_impact_2021, title = {The Impact of Binaries on the Evolution of Star Clusters from Turbulent Molecular Clouds}, author = {Torniamenti, Stefano and Ballone, Alessandro and Mapelli, Michela and Gaspari, Nicola and Di Carlo, Ugo N. and Rastello, Sara and Giacobbo, Nicola and Pasquato, Mario}, year = {2021}, month = apr, journal = {arXiv:2104.12781 [astro-ph]}, eprint = {2104.12781}, primaryclass = {astro-ph}, urldate = {2021-04-28}, abstract = {Most of massive stars form in binary or higher-order systems in clumpy, sub-structured clusters. In the very first phases of their life, these stars are expected to interact with the surrounding environment, before being released to the field when the cluster is tidally disrupted by the host galaxy. We present a set of N-body simulations to describe the evolution of young stellar clusters and their binary content in the first phases of their life. To do this, we have developed a method that generates realistic initial conditions for binary stars in star clusters from hydrodynamical simulations. We considered different evolutionary cases to quantify the impact of binary and stellar evolution. Also, we compared their evolution to that of King and fractal models with different length scales. Our results indicate that the global expansion of the cluster from hydrodynamical simulations is initially balanced by the sub-clump motion and accelerates when a monolithic shape is reached, as in a post-core collapse evolution. Compared to the spherical initial conditions, the ratio of the 50\% to 10\% Lagrangian radius shows a very distinctive trend, explained by the formation of a hot core of massive stars triggered by the high initial degree of mass segregation. As for its binary population, each cluster shows a self-regulating behaviour by creating interacting binaries with binding energies of the order of its energy scales. Also, in absence of original binaries, the dynamically formed binaries present a mass dependent binary fraction, that mimics the trend of the observed one.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\F3SL7JYZ\\2104.html}}
@misc{torniamenti_stellarmass_black_2023, title = {Stellar-Mass Black Holes in the {{Hyades}} Star Cluster?}, author = {Torniamenti, Stefano and Gieles, Mark and Penoyre, Zephyr and Jerabkova, Tereza and Wang, Long and Anders, Friedrich}, year = {2023}, month = mar, number = {arXiv:2303.10188}, eprint = {2303.10188}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.10188}, urldate = {2023-03-23}, abstract = {Astrophysical models of binary-black hole mergers in the Universe require a significant fraction of stellar-mass black holes (BHs) to receive negligible natal kicks to explain the gravitational wave detections. This implies that BHs should be retained even in open clusters with low escape velocities (\$\textbackslash lesssim1\textasciitilde\textbackslash mathrm\{km \textbackslash, s\^\{-1\}\}\$). We search for signatures of the presence of BHs in the nearest open cluster to the Sun - the Hyades - by comparing density profiles of direct \$N\$-body models to data from \$Gaia\$. The observations are best reproduced by models with \$2-3\$ BHs at present. Models that never possessed BHs have an half-mass radius \$\textbackslash sim30\textbackslash\%\$ smaller than the observed value, while those where the last BHs were ejected recently (\$\textbackslash lesssim150\textasciitilde\$Myr ago) can still reproduce the density profile. In 50\% of the models hosting BHs, we find BHs with stellar companion(s). Their period distribution peaks at \$\textbackslash sim10\^3\$ yr, making them unlikely to be found through velocity variations. We look for potential BH companions through large \$Gaia\$ astrometric and spectroscopic errors, identifying 56 binary candidates - none of which consistent with a massive compact companion. Models with \$2-3\$ BHs have an elevated central velocity dispersion, but observations can not yet discriminate. We conclude that the present-day structure of the Hyades requires a significant fraction of BHs to receive natal kicks smaller than the escape velocity of \$\textbackslash sim 3\textbackslash, \textbackslash mathrm\{km \textbackslash, s\^\{-1\}\}\$ at the time of BH formation and that the nearest BHs to the Sun are in, or near, Hyades.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@misc{turner_color-magnitude_1996, title = {Color-{{Magnitude Diagrams}} for {{Young Open Clusters}}}, author = {Turner, David G.}, year = {1996}, urldate = {2019-10-18}, howpublished = {http://articles.adsabs.harvard.edu/pdf/1996ASPC...90..443T}, file = {C\:\\Users\\Emily\\Zotero\\storage\\9FH3PDXP\\Turner_1996_Color-Magnitude Diagrams for Young Open Clusters.pdf}}
@article{vaidya_blue_2020, title = {Blue {{Straggler Populations}} of {{Seven Open Clusters}} with {{Gaia DR2}}}, author = {Vaidya, Kaushar and Rao, Khushboo K. and Agarwal, Manan and Bhattacharya, Souradeep}, year = {2020}, month = jun, journal = {arXiv:2006.05189 [astro-ph]}, eprint = {2006.05189}, primaryclass = {astro-ph}, urldate = {2020-06-15}, abstract = {Blue straggler stars (BSS) are well studied in globular clusters but their systematic study with secure membership determination is lacking in open clusters. We use Gaia DR2 data to determine accurate stellar membership for four intermediate-age open clusters, Melotte 66, NGC 2158, NGC 2506 and NGC 6819, and three old open clusters, Berkeley 39, NGC 188 and NGC 6791, to subsequently study their BSS populations. The BSS radial distributions of five clusters, Melotte 66, NGC 188, NGC 2158, NGC 2506, and NGC 6791, show bimodal distributions, placing them with Family II globular clusters which are of intermediate dynamical ages. The location of minima, \$r\_\textbackslash mathrm\{\{min\}\}\$, in the bimodal BSS radial distributions, varies from 1.5\$r\_c\$ to 4.0\$r\_c\$, where \$r\_c\$ is the core radius of the clusters. We find a positive correlation between \$r\_\textbackslash mathrm\{\{min\}\}\$ and \$N\_\{\textbackslash mathrm\{relax\}\}\$, the ratio of cluster age to the current central relaxation time of the cluster. We further report that this correlation is consistent in its slope, within the errors, to the slope of the globular cluster correlation between the same quantities, but with a slightly higher intercept. This is the first example in open clusters that shows BSS radial distributions as efficient probes of dynamical age. The BSS radial distributions of the remaining two clusters, Berkeley 39 and NGC 6819, are flat. The estimated \$N\_\{\textbackslash mathrm\{relax\}\}\$ values of these two clusters, however, indicate that they are dynamically evolved. Berkeley 39 especially has its entire BSS population completely segregated to the inner regions of the cluster.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NQR6P6B9\\2006.html}}
@article{valle_goodness--fit_2021, title = {Goodness-of-Fit Test for Isochrone Fitting in the {{Gaia}} Era. {{Statistical}} Assessment of the Error Distribution}, author = {Valle, G. and Dell'Omodarme, M. and Tognelli, E.}, year = {2021}, month = mar, journal = {arXiv:2103.08209 [astro-ph]}, eprint = {2103.08209}, primaryclass = {astro-ph}, urldate = {2021-03-17}, abstract = {[...] This paper presents a rigorous derivation of a goodness-of-fit statistics for colour-magnitude diagrams (CMD). We discuss the reliability of the underlying assumptions and their validity. We derived the distribution of the sum of squared Mahalanobis distances of stellar data and theoretical isochrone for a generic set of data and models. We applied this to the case of synthetic CMDs constructed to mimic real data of open clusters in the GAIA sample. We analysed the capability of distinguishing among different sets of input physics and parameters that were used to compute the stellar models. We generated synthetic clusters from isochrones computed with these perturbed quantities, and we evaluated the goodness-of-fit with respect to the unperturbed isochrone. We show that when \$r\$ magnitudes are available for each of the \$N\$ observational objects and \$p\$ hyperparameters are estimated in the fit, the error distribution follows a \$\textbackslash chi\^2\$ distribution with \$(r-1)N - p\$ degrees of freedom. We show that the linearisation of the isochrone causes negligible deviation from this result. We investigated the possibility of detecting the effects on stellar models that are induced when varying convective core overshooting efficiency, \$\^\{14\}\$N\$(p,\textbackslash gamma)\^\{15\}\$O reaction rate, microscopic diffusion velocities, outer BCs, and colour transformation. The results suggest that it is possible to detect the effect induced by only some of the perturbed quantities. [...] A variation in the convective core overshooting efficiency was detectable only for photometric errors of 0.003 mag and only for the 1 Gyr case. The effects induced by the outer boundary conditions and the bolometric corrections are the largest. [...] As a last exercise, we addressed the validity of the goodness-of-fit statistics for real-world open cluster CMDs, contaminated by field stars or unresolved binaries. [...]}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JA6FKGTU\\2103.html}}
@misc{van_groeningen_machine_2023, title = {A Machine Learning-Based Tool for Open Cluster Membership Determination in {{Gaia DR3}}}, author = {{van Groeningen}, M. G. J. and {Castro-Ginard}, A. and Brown, A. G. A. and Casamiquela, L. and Jordi, C.}, year = {2023}, month = mar, number = {arXiv:2303.08474}, eprint = {2303.08474}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2303.08474}, urldate = {2023-03-16}, abstract = {Membership studies characterising open clusters with Gaia data, most using DR2, are so far limited at magnitude G = 18 due to astrometric uncertainties at the faint end. Our goal is to extend current open cluster membership lists with faint members and to characterise the low-mass end, which members are important for many applications, in particular for ground-based spectroscopic surveys. We use a deep neural network architecture to learn the distribution of highly reliable open cluster member stars around known clusters. After that, we use the trained network to estimate new open cluster members based on their similarities in a high-dimensional space, five-dimensional astrometry plus the three photometric bands. Due to the improved astrometric precisions of Gaia DR3 with respect to DR2, we are able to homogeneously detect new faint member stars (G {$>$} 18) for the known open cluster population. Our methodology can provide extended membership lists for open clusters down to the limiting magnitude of Gaia, which will enable further studies to characterise the open cluster population, e.g. estimation of their masses, or their dynamics. These extended membership lists are also ideal target lists for forthcoming ground-based spectroscopic surveys.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@book{van_rossum_python_2009, title = {Python 3 {{Reference Manual}}}, author = {Van Rossum, Guido and Drake, Fred L.}, year = {2009}, publisher = {{CreateSpace}}, address = {{Scotts Valley, CA}}, abstract = {PYTHON 3 Reference Manual (Python Documentation MANUAL Part 2).Python is an easy to learn object-oriented programming language, which combines power with clear syntax. It has modules, classes, exceptions, very high level data types, and dynamic typing. Python is free software. It can be used with GNU (GNU/Linux), Unix, Microsoft Windows and many other systems.This is a printed softcover copy of the official Python documentation from the latest Python 3.0 distribution. For each copy sold \$1 will be donated to the Python Software Foundation by the publisher.This book is part of a brand new six-part series of Python documentation books. Searching for "Python Documentation Manual" will show all six available books.ABOUT THE AUTHOR: Guido van Rossum, is the inventor of Python. Fred L. Drake, Jr. is the official editor of the Python documentation.}, isbn = {978-1-4414-1269-0}}
@book{vanleeuwen_hipparcos_new_2007, title = {Hipparcos, the New Reduction of the Raw Data}, author = {{van Leeuwen}, Floor}, year = {2007}, volume = {350}, doi = {10.1007/978-1-4020-6342-8}, adsnote = {Provided by the SAO/NASA Astrophysics Data System}, adsurl = {https://ui.adsabs.harvard.edu/abs/2007ASSL..350.....V}}
@article{vanleeuwen_parallaxes_proper_2009, title = {Parallaxes and Proper Motions for 20 Open Clusters as Based on the New {{Hipparcos}} Catalogue}, author = {{van Leeuwen}, F.}, year = {2009}, month = apr, journal = {Astronomy and Astrophysics}, volume = {497}, pages = {209--242}, issn = {0004-6361}, doi = {10.1051/0004-6361/200811382}, urldate = {2023-04-26}, abstract = {Context: A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude Hp = 8 are improved, by up to a factor 4, compared to the original catalogue. As correlations between the underlying abscissa residuals have also been reduced by more than an order of magnitude to an insignificant level, our ability to determine reliable parallaxes and proper motions for open clusters should be improved. Aims: The new Hipparcos astrometric catalogue is used to derive mean parallax and proper motion estimates for 20 open clusters. The HR-diagrams of the nearest clusters are compared and combined to provide future input to sets of observational isochrones. Methods: Three different methods are applied, according to the proximity of the cluster, to compensate, where needed, for projection effects, spread in position along the line of sight, and the internal velocity dispersion of the cluster stars. Results: The new parallaxes have accuracies between 2 and 2.5 times higher than what had been derived from the original Hipparcos catalogue. At least two to three groups of clusters, mostly of similar ages, are observed to each occupy their own specific space in the HR diagram. A significant discrepancy in distance moduli from those obtained with isochrone-based main-sequence fitting remains, in particular for one of these groups, containing the Pleiades, NGC 2516, and Blanco 1. The difference in absolute magnitudes between this group and one containing the Hyades and Praesepe clusters appears to be correlated with systematic differences in the Str\"omgren {$\Delta$} c0 index between those groups. The same dependency has been known to exist for a long time, and is again confirmed by the Hipparcos data, in variations in absolute magnitudes for field stars of the same effective temperature. Conclusions: The positions of the cluster HR diagrams are consistent within different groups of clusters shown for example by the near-perfect alignment of the sequences for the Hyades and Praesepe, for Coma Ber and UMa, and for the Pleiades, NGC 2516, and Blanco 1. The groups are mutually consistent when systematic differences in {$\Delta$} c0 are taken into account, where the effect of these differences on the absolute magnitudes has been calibrated using field-star observations.}, keywords = {astrometry,Astrophysics - Galaxy Astrophysics,Astrophysics - Instrumentation and Methods for Astrophysics,Hertzsprung-Russell (HR) and C-M diagrams,methods: data analysis,open clusters and associations: general,stars: distances}, annotation = {ADS Bibcode: 2009A\&A...497..209V}}
@article{vasiliev_gaia_2021, title = {Gaia {{EDR3}} View on {{Galactic}} Globular Clusters}, author = {Vasiliev, Eugene and Baumgardt, Holger}, year = {2021}, month = feb, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {505}, number = {4}, eprint = {2102.09568}, pages = {5978--6002}, urldate = {2021-02-24}, abstract = {We use the data from Gaia Early Data Release 3 (EDR3) to study the kinematic properties of Milky Way globular clusters. We measure the mean parallaxes and proper motions (PM) for 170 clusters, determine the PM dispersion profiles for more than 100 clusters, uncover rotation signatures in more than 20 objects, and find evidence for radial or tangential PM anisotropy in a dozen richest clusters. At the same time, we use the selection of cluster members to explore the reliability and limitations of the Gaia catalogue itself. We find that the formal uncertainties on parallax and PM are underestimated by 10-20\% in dense central regions even for stars that pass numerous quality filters. We explore the the spatial covariance function of systematic errors, and determine a lower limit on the uncertainty of average parallaxes and PM at the level 0.01 mas and 0.025 mas/yr, respectively. Finally, a comparison of mean parallaxes of clusters with distances from various literature sources suggests that the parallaxes (after applying the zero-point correction suggested by Lindegren et al. 2020) are overestimated by 0.006-0.009 mas. Despite these caveats, the quality of Gaia astrometry has been significantly improved in EDR3 and provides valuable insights into the properties of star clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\F5SPZ2D9\\2102.html}}
@article{vazquez_gaia-eso_2022, title = {The {{Gaia-ESO Survey}}: {{Age-chemical-clock}} Relations Spatially Resolved in the {{Galactic}} Disc}, shorttitle = {The {{Gaia-ESO Survey}}}, author = {V{\'a}zquez, C. Viscasillas and Magrini, L. and Casali, G. and Tautvai{\v s}ien{\.e}, G. and Spina, L. and {Van der Swaelmen}, M. and Randich, S. and Bensby, T. and Bragaglia, A. and Friel, E. and Feltzing, S. and Sacco, G. G. and Turchi, A. and {Jim{\'e}nez-Esteban}, F. and D'Orazi, V. and {Delgado-Mena}, E. and Mikolaitis, {\v S} and Drazdauskas, A. and Minkevi{\v c}i{\=u}t{\.e}, R. and Stonkut{\.e}, E. and Bagdonas, V. and Montes, D. and Guiglion, G. and Baratella, M. and Tabernero, H. M. and Gilmore, G. and Alfaro, E. and Francois, P. and Korn, A. and Smiljanic, R. and Bergemann, M. and Franciosini, E. and Gonneau, A. and Hourihane, A. and Worley, C. C. and Zaggia, S.}, year = {2022}, month = feb, journal = {arXiv:2202.04863 [astro-ph]}, eprint = {2202.04863}, primaryclass = {astro-ph}, urldate = {2022-02-14}, abstract = {The last decade has seen a revolution in our knowledge of the Galaxy thanks to the Gaia and asteroseismic space missions and the ground-based spectroscopic surveys. To complete this picture, it is necessary to map the ages of its stellar populations. During recent years, the dependence on time of abundance ratios involving slow (s) neutron-capture and \$\textbackslash alpha\$ elements (called chemical-clocks) has been used to provide estimates of stellar ages, usually in a limited volume close to the Sun. We aim to analyse the relations of chemical clocks in the Galactic disc extending the range to R\$\_\{\textbackslash rm GC\}\textbackslash sim\$6-20\textasciitilde kpc. Using the sixth internal data release of the Gaia-ESO survey, we calibrated several relations between stellar ages and abundance ratios [s/\$\textbackslash alpha\$] using a sample of open clusters, the largest one so far used with this aim. Thanks to their wide galactocentric coverage, we investigated the radial variations of the shape of these relations, confirming their non-universality. We estimated our accuracy and precision in recovering the global ages of open clusters, and the ages of their individual members. We applied the multi-variate relations with the highest correlation coefficients to the field star population. We confirm that there is no single age-chemical clock relationship valid for the whole disc, but that there is a dependence on the galactocentric position, which is related to the radial variation of the star formation history combined with the non-monotonic dependence on metallicity of the yields of the s-process elements from low- and intermediate-mass stars. Finally, the abundance ratios [Ba/\$\textbackslash alpha\$] are more sensitive to age than those with [Y/\$\textbackslash alpha\$] for young disc stars, and their slopes vary less with galactocentric distance.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\HZGLENIQ\\2202.html}}
@article{virtanen_scipy_2020, title = {{{SciPy}} 1.0: Fundamental Algorithms for Scientific Computing in {{Python}}}, author = {Virtanen, Pauli and Gommers, Ralf and Oliphant, Travis E. and Haberland, Matt and Reddy, Tyler and Cournapeau, David and Burovski, Evgeni and Peterson, Pearu and Weckesser, Warren and Bright, Jonathan and {van der Walt}, St{\'e}fan J. and Brett, Matthew and Wilson, Joshua and Millman, K. Jarrod and Mayorov, Nikolay and Nelson, Andrew R. J. and Jones, Eric and Kern, Robert and Larson, Eric and Carey, C. J. and Polat, {\.I}lhan and Feng, Yu and Moore, Eric W. and VanderPlas, Jake and Laxalde, Denis and Perktold, Josef and Cimrman, Robert and Henriksen, Ian and Quintero, E. A. and Harris, Charles R. and Archibald, Anne M. and Ribeiro, Ant{\^o}nio H. and Pedregosa, Fabian and {van Mulbregt}, Paul and Vijaykumar, Aditya and Bardelli, Alessandro Pietro and Rothberg, Alex and Hilboll, Andreas and Kloeckner, Andreas and Scopatz, Anthony and Lee, Antony and Rokem, Ariel and Woods, C. Nathan and Fulton, Chad and Masson, Charles and H{\"a}ggstr{\"o}m, Christian and Fitzgerald, Clark and Nicholson, David A. and Hagen, David R. and Pasechnik, Dmitrii V. and Olivetti, Emanuele and Martin, Eric and Wieser, Eric and Silva, Fabrice and Lenders, Felix and Wilhelm, Florian and Young, G. and Price, Gavin A. and Ingold, Gert-Ludwig and Allen, Gregory E. and Lee, Gregory R. and Audren, Herv{\'e} and Probst, Irvin and Dietrich, J{\"o}rg P. and Silterra, Jacob and Webber, James T. and Slavi{\v c}, Janko and Nothman, Joel and Buchner, Johannes and Kulick, Johannes and Sch{\"o}nberger, Johannes L. and {de Miranda Cardoso}, Jos{\'e} Vin{\'i}cius and Reimer, Joscha and Harrington, Joseph and Rodr{\'i}guez, Juan Luis Cano and {Nunez-Iglesias}, Juan and Kuczynski, Justin and Tritz, Kevin and Thoma, Martin and Newville, Matthew and K{\"u}mmerer, Matthias and Bolingbroke, Maximilian and Tartre, Michael and Pak, Mikhail and Smith, Nathaniel J. and Nowaczyk, Nikolai and Shebanov, Nikolay and Pavlyk, Oleksandr and Brodtkorb, Per A. and Lee, Perry and McGibbon, Robert T. and Feldbauer, Roman and Lewis, Sam and Tygier, Sam and Sievert, Scott and Vigna, Sebastiano and Peterson, Stefan and More, Surhud and Pudlik, Tadeusz and Oshima, Takuya and Pingel, Thomas J. and Robitaille, Thomas P. and Spura, Thomas and Jones, Thouis R. and Cera, Tim and Leslie, Tim and Zito, Tiziano and Krauss, Tom and Upadhyay, Utkarsh and Halchenko, Yaroslav O. and {V{\'a}zquez-Baeza}, Yoshiki and {SciPy 1.0 Contributors}}, year = {2020}, month = mar, journal = {Nature Methods}, volume = {17}, number = {3}, pages = {261--272}, issn = {1548-7105}, doi = {10.1038/s41592-019-0686-2}, abstract = {SciPy is an open-source scientific computing library for the Python programming language. Since its initial release in 2001, SciPy has become a de facto standard for leveraging scientific algorithms in Python, with over 600 unique code contributors, thousands of dependent packages, over 100,000 dependent repositories and millions of downloads per year. In this work, we provide an overview of the capabilities and development practices of SciPy 1.0 and highlight some recent technical developments.}}
@article{vitral_balrogo_2021, title = {{{BALRoGO}}: {{Bayesian Astrometric Likelihood Recovery}} of {{Galactic Objects}} -- {{Global}} Properties of over One Hundred Globular Clusters with {{Gaia EDR3}}}, shorttitle = {{{BALRoGO}}}, author = {Vitral, Eduardo}, year = {2021}, month = feb, journal = {arXiv:2102.04841 [astro-ph]}, eprint = {2102.04841}, primaryclass = {astro-ph}, urldate = {2021-02-10}, abstract = {We present BALRoGO: Bayesian Astrometric Likelihood Recovery of Galactic Objects, a public code to measure the centers, effective radii, and bulk proper motions of Milky Way globular clusters and Local Group dwarf spheroidals, whose data are mixed with Milky Way field stars. Our approach presents innovative methods such as surface density fits allowing for strong interloper contamination and proper motion fits using a Pearson VII distribution for interlopers, instead of classic Gaussian-mixture recipes. We also use non-parametric approaches to represent the color-magnitude diagram of such stellar systems based in their membership probabilities, previously derived from surface density and proper motion fits. The robustness of our method is verified by comparing its results with previous estimates from the literature as well as by testing it on mock data from N-body simulations. We applied BALRoGO to Gaia EDR3 data for over one hundred Milky Way globular clusters and nine Local Group dwarf spheroidals, and we provide positions, effective radii, and bulk proper motions. Finally, we make our algorithm available as an open source software.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Instrumentation and Methods for Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\S3R2VHCG\\2102.html}}
@article{vitral_does_2021, title = {Does {{NGC}} 6397 Contain an Intermediate-Mass Black Hole or a More Diffuse Inner Subcluster?}, author = {Vitral, Eduardo and Mamon, Gary A.}, year = {2021}, month = feb, journal = {Astronomy and Astrophysics}, volume = {646}, pages = {A63}, issn = {0004-6361}, doi = {10.1051/0004-6361/202039650}, urldate = {2022-03-28}, abstract = {We analyze proper motions from the Hubble Space Telescope (HST) and the second Gaia data release along with line-of-sight velocities from the MUSE spectrograph to detect imprints of an intermediate-mass black hole (IMBH) in the center of the nearby, core-collapsed, globular cluster NGC 6397. For this, we use the new MAMPOSST-PM Bayesian mass-modeling code, along with updated estimates of the surface density profile of NGC 6397. We consider different priors on velocity anisotropy and on the size of the central mass, and we also separate the stars into components of different mean mass to allow for mass segregation. The velocity ellipsoid is very isotropic throughout the cluster, as expected in post-core collapsed clusters subject to as strong a Galactic tidal field as NGC 6397. There is strong evidence for a central dark component of 0.8 to 2\% of the total mass of the cluster. However, we find robust evidence disfavoring a central IMBH in NGC 6397, preferring instead a diffuse dark inner subcluster of unresolved objects with a total mass of 1000 to 2000 M\textsubscript{{$\odot$}}, half of which is concentrated within 6 arcsec (2\% of the stellar effective radius). These results require the combination of HST and Gaia data: HST for the inner diagnostics and Gaia for the outer surface density and velocity anisotropy profiles. The small effective radius of the diffuse dark component suggests that it is composed of compact stars (white dwarfs and neutron stars) and stellar-mass black holes, whose inner locations are caused by dynamical friction given their high progenitor masses. We show that stellar-mass black holes should dominate the mass of this diffuse dark component, unless more than 25\% escape from the cluster. Their mergers in the cores of core-collapsed globular clusters could be an important source of the gravitational wave events detected by LIGO.}, langid = {english}}
@article{walkowicz_choose_2018, title = {Choose {{Your Own Adventure}}: {{Developing A Values-Oriented Framework}} for {{Your Career}}}, shorttitle = {Choose {{Your Own Adventure}}}, author = {Walkowicz, Lucianne M.}, year = {2018}, month = may, journal = {arXiv:1805.09963 [astro-ph, physics:physics]}, eprint = {1805.09963}, primaryclass = {astro-ph, physics:physics}, urldate = {2020-08-21}, abstract = {We've all heard how academia evaluates our work: papers, papers, and... more papers. While academic publishing is an essential part of disseminating research results, it is only one activity amongst many that make up a career (or for that matter, a life). The following essay is based on an invited talk for the NSF AAPF Symposium, given at the 2018 Winter AAS Meeting. Here, as in the original talk, I offer some practical advice for thinking about one's work within the larger frame of your personal values and goals. While I will draw examples from my own career, I hope to offer readers guidance in articulating what is important to them, aligning their career choices with those values, and establishing metrics that go beyond the h-index.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,Astrophysics - Earth and Planetary Astrophysics,Astrophysics - High Energy Astrophysical Phenomena,Astrophysics - Solar and Stellar Astrophysics,Physics - Physics Education}, file = {C\:\\Users\\Emily\\Zotero\\storage\\7T9SR3DZ\\1805.html}}
@article{wall_modelling_2020, title = {Modelling of the {{Effects}} of {{Stellar Feedback}} during {{Star Cluster Formation Using}} a {{Hybrid Gas}} and {{N-Body Method}}}, author = {Wall, Joshua E. and Mac Low, Mordecai-Mark and McMillan, Stephen L. W. and Klessen, Ralf S. and Zwart, Simon Portegies and Pellegrino, Andrew}, year = {2020}, month = oct, journal = {arXiv:2003.09011 [astro-ph]}, eprint = {2003.09011}, primaryclass = {astro-ph}, urldate = {2020-10-13}, abstract = {Understanding the formation of stellar clusters requires following the interplay between gas and newly formed stars accurately. We therefore couple the magnetohydrodynamics code FLASH to the N-body code ph4 and the stellar evolution code SeBa using the Astrophysical Multipurpose Software Environment (AMUSE) to model stellar dynamics, evolution, and collisional N-body dynamics and the formation of binary and higher-order multiple systems, while implementing stellar feedback in the form of radiation, stellar winds and supernovae in FLASH. We here describe the algorithms used for each of these processes. We denote this integrated package Torch. We then use this novel numerical method to simulate the formation and early evolution of several examples of open clusters of \textasciitilde 1000 stars formed from clouds with a mass range of 10\^3-10\^5 M\_sun. Analyzing the effects of stellar feedback on the gas and stars of the natal clusters, we find that in these examples, the stellar clusters are resilient to disruption, even in the presence of intense feedback. This can even slightly increase the amount of dense, Jeans unstable gas by sweeping up shells; thus, a stellar wind strong enough to trap its own H II region shows modest triggering of star formation. Our clusters are born moderately mass segregated, an effect enhanced by feedback, and retained after the ejection of their natal gas, in agreement with observations.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YREMW4S9\\2003.html}}
@article{wang_effects_2019, title = {Effects of Close Binary Evolution on the Main-Sequence Morphology of Young Star Clusters}, author = {Wang, Chen and Langer, Norbert and Schootemeijer, Abel and Castro, Norberto and Adscheid, Sylvia and Marchant, Pablo and Hastings, Ben}, year = {2019}, month = dec, journal = {arXiv:1912.07294 [astro-ph]}, eprint = {1912.07294}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {Star clusters are the building blocks of galaxies. They are composed of stars of nearly equal age and chemical composition, allowing us to use them as chronometers and as testbeds for gauging stellar evolution. It has become clear recently that massive stars are formed preferentially in close binaries, in which mass transfer will drastically change the evolution of the stars. This is expected to leave a significant imprint in the distribution of cluster stars in the Hertzsprung-Russell diagram. Our results, based on a dense model grid of more than 50 000 detailed binary evolution calculations, indeed show several distinct, coeval main-sequence components, most notably an extended main-sequence turn-off region, and a group of near-critically rotating stars that is spread over a large luminosity range on the red side of the classical main sequence. We comprehensively demonstrate the time evolution of the features in an animation, and we derive analytic expressions to describe these features. We find quantitative agreement with results based on recent photometric and spectroscopic observations. We conclude that while other factors may also be at play, binary evolution has a major impact on the main-sequence morphology of young star clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\WNXSRBCM\\1912.html}}
@article{wang_stellar_2022, title = {Stellar Mergers as the Origin of the Blue Main-Sequence Band in Young Star Clusters}, author = {Wang, Chen and Langer, Norbert and Schootemeijer, Abel and Milone, Antonino and Hastings, Ben and Xu, Xiao-Tian and Bodensteiner, Julia and Sana, Hugues and Castro, Norberto and Lennon, D. J. and Marchant, Pablo and {de Koter}, A. and {de Mink}, Selma E.}, year = {2022}, month = feb, journal = {Nature Astronomy}, eprint = {2202.05552}, issn = {2397-3366}, doi = {10.1038/s41550-021-01597-5}, urldate = {2022-02-14}, abstract = {Recent high-quality Hubble Space Telescope (HST) photometry shows that the main sequences (MS) stars of young star clusters form two discrete components in the color-magnitude diagram (CMD). Based on their distribution in the CMD, we show that stars of the blue MS component can be understood as slow rotators originating from stellar mergers. We derive the masses of the blue MS stars, and find that they follow a nearly flat mass function, which supports their unusual formation path. Our results imply that the cluster stars gain their mass in two different ways, by disk accretion leading to rapid rotation, contributing to the red MS, or by binary merger leading to slow rotation and populating the blue MS. We also derive the approximate merger time of the individual stars of the blue MS component, and find a strong early peak in the merger rate, with a lower level merger activity prevailing for tens of Myr. This supports recent binary formation models, and explains new velocity dispersion measurements for members of young star clusters. Our findings shed new light on the origin of the bi-modal mass, spin, and magnetic field distributions of main-sequence stars.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\EBQTL2DA\\2202.html}}
@article{ward_not_2019, title = {Not All Stars Form in Clusters -- \${{Gaia}}\$-{{DR2}} Uncovers the Origin of {{OB}} Associations}, author = {Ward, Jacob L. and Kruijssen, J. M. Diederik and Rix, Hans-Walter}, year = {2019}, month = oct, journal = {arXiv:1910.06974 [astro-ph]}, eprint = {1910.06974}, primaryclass = {astro-ph}, urldate = {2019-10-18}, abstract = {Historically, it has often been asserted that most stars form in compact clusters. In this scenario, present-day gravitationally-unbound OB associations are the result of the expansion of initially gravitationally-bound star clusters. However, this paradigm is inconsistent with recent results, both theoretical and observational, that instead favour a hierarchical picture of star formation in which stars are formed across a continuous distribution of gas densities and most OB associations never were bound clusters. Instead they are formed in-situ as the low-density side of this distribution, rather than as the remnants of expanding clusters. We utilise the second \$Gaia\$ data release to quantify the degree to which OB associations are undergoing expansion and, therefore, whether OB associations are the product of expanding clusters, or whether they were born in-situ, as the large-scale, globally-unbound associations that we see today. We find that the observed kinematic properties of associations are consistent with highly substructured velocity fields and additionally require some degree of localised expansion from sub-clusters within the association. While most present-day OB associations do exhibit low levels of expansion, there is no significant correlation between radial velocity and radius. Therefore, the large-scale structure of associations is not set by the expansion of clusters, rather it is a relic of the molecular gas cloud from which the association was formed. This finding is inconsistent with a monolithic model of association formation and instead favours a hierarchical model, in which OB associations form in-situ, following the fractal structure of the gas from which they form.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\JZDHWS38\\1910.html}}
@article{wen_flipout_2018, title = {Flipout: {{Efficient Pseudo-Independent Weight Perturbations}} on {{Mini-Batches}}}, shorttitle = {Flipout}, author = {Wen, Yeming and Vicol, Paul and Ba, Jimmy and Tran, Dustin and Grosse, Roger}, year = {2018}, month = apr, journal = {arXiv e-prints}, volume = {arXiv:1803.04386}, urldate = {2022-03-31}, abstract = {Stochastic neural net weights are used in a variety of contexts, including regularization, Bayesian neural nets, exploration in reinforcement learning, and evolution strategies. Unfortunately, due to the large number of weights, all the examples in a mini-batch typically share the same weight perturbation, thereby limiting the variance reduction effect of large mini-batches. We introduce flipout, an efficient method for decorrelating the gradients within a mini-batch by implicitly sampling pseudo-independent weight perturbations for each example. Empirically, flipout achieves the ideal linear variance reduction for fully connected networks, convolutional networks, and RNNs. We find significant speedups in training neural networks with multiplicative Gaussian perturbations. We show that flipout is effective at regularizing LSTMs, and outperforms previous methods. Flipout also enables us to vectorize evolution strategies: in our experiments, a single GPU with flipout can handle the same throughput as at least 40 CPU cores using existing methods, equivalent to a factor-of-4 cost reduction on Amazon Web Services.}, keywords = {Computer Science - Machine Learning,Statistics - Machine Learning}}
@article{wenger_m_simbad_2000, title = {The {{SIMBAD}} Astronomical Database - {{The CDS}} Reference Database for Astronomical Objects}, author = {{Wenger, M.} and {Ochsenbein, F.} and {Egret, D.} and {Dubois, P.} and {Bonnarel, F.} and {Borde, S.} and {Genova, F.} and {Jasniewicz, G.} and {Lalo\"e, S.} and {Lesteven, S.} and {Monier, R.}}, year = {2000}, journal = {Astron. Astrophys. Suppl. Ser.}, volume = {143}, number = {1}, pages = {9--22}, doi = {10.1051/aas:2000332}}
@article{whitmore_star_2021, title = {Star {{Cluster Classification}} in the {{PHANGS-HST Survey}}: {{Comparison}} between {{Human}} and {{Machine Learning Approaches}}}, shorttitle = {Star {{Cluster Classification}} in the {{PHANGS-HST Survey}}}, author = {Whitmore, Bradley C. and Lee, Janice C. and Chandar, Rupali and Thilker, David A. and Hannon, Stephen and Wei, Wei and Huerta, E. A. and Bigiel, Frank and Boquien, M{\'e}d{\'e}ric and Chevance, M{\'e}lanie and Dale, Daniel A. and Deger, Sinan and Grasha, Kathryn and Klessen, Ralf S. and Kruijssen, J. M. Diederik and Larson, Kirsten L. and Mok, Angus and Rosolowsky, Erik and Schinnerer, Eva and Schruba, Andreas and Ubeda, Leonardo and Van Dyk, Schuyler D. and Watkins, Elizabeth and Williams, Thomas}, year = {2021}, month = aug, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {506}, number = {4}, eprint = {2107.13049}, pages = {5294--5317}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/stab2087}, urldate = {2021-09-15}, abstract = {When completed, the PHANGS-HST project will provide a census of roughly 50,000 compact star clusters and associations, as well as human morphological classifications for roughly 20,000 of those objects. These large numbers motivated the development of a more objective and repeatable method to help perform source classifications. In this paper we consider the results for five PHANGS-HST galaxies (NGC 628, NGC 1433, NGC 1566, NGC 3351, NGC 3627) using classifications from two convolutional neural network architectures (RESNET and VGG) trained using deep transfer learning techniques. The results are compared to classifications performed by humans. The primary result is that the neural network classifications are comparable in quality to the human classifications with typical agreement around 70 to 80\$\textbackslash\%\$ for Class 1 clusters (symmetric, centrally concentrated) and 40 to 70\$\textbackslash\%\$ for Class 2 clusters (asymmetric, centrally concentrated). If Class 1 and 2 are considered together the agreement is 82 \$\textbackslash pm\$ 3\$\textbackslash\%\$. Dependencies on magnitudes, crowding, and background surface brightness are examined. A detailed description of the criteria and methodology used for the human classifications is included along with an examination of systematic differences between PHANGS-HST and LEGUS. The distribution of data points in a colour-colour diagram is used as a 'figure of merit' to further test the relative performances of the different methods. The effects on science results (e.g., determinations of mass and age functions) of using different cluster classification methods are examined and found to be minimal.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6MRZZXCF\\2107.html}}
@article{winter_stellar_2020, title = {Stellar Clustering Shapes the Architectures of Planetary Systems}, author = {Winter, Andrew J. and Kruijssen, J. M. Diederik and Longmore, Steven N. and Chevance, M{\'e}lanie}, year = {2020}, month = oct, journal = {Nature}, volume = {586}, number = {7830}, eprint = {2010.10531}, pages = {528--532}, issn = {0028-0836, 1476-4687}, doi = {10.1038/s41586-020-2800-0}, urldate = {2020-10-22}, abstract = {Planet formation is generally described in terms of a system containing the host star and a protoplanetary disc, of which the internal properties (e.g. mass and metallicity) determine the properties of the resulting planetary system. However, (proto)planetary systems are predicted and observed to be affected by the spatially-clustered stellar formation environment, either through dynamical star-star interactions or external photoevaporation by nearby massive stars. It is challenging to quantify how the architecture of planetary systems is affected by these environmental processes, because stellar groups spatially disperse within {$<$}1 billion years, well below the ages of most known exoplanets. Here we identify old, co-moving stellar groups around exoplanet host stars in the astrometric data from the Gaia satellite and demonstrate that the architecture of planetary systems exhibits a strong dependence on local stellar clustering in position-velocity phase space, implying a dependence on their formation or evolution environment. After controlling for host stellar age, mass, metallicity, and distance from the Sun, we obtain highly significant differences (with \$p\$-values of \$10\^\{-5\}\{-\}10\^\{-2\}\$) in planetary (system) properties between phase space overdensities and the field. The median semi-major axis and orbital period of planets in overdensities are 0.087 au and 9.6 days, respectively, compared to 0.81 au and 154 days for planets around field stars. 'Hot Jupiters' (massive, close-in planets) predominantly exist in stellar phase space overdensities, strongly suggesting that their extreme orbits originate from environmental perturbations rather than internal migration or planet-planet scattering. Our findings reveal that stellar clustering is a key factor setting the architectures of planetary systems.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Earth and Planetary Astrophysics,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\F5DTK8G4\\2010.html}}
@article{wolf_accurate_2010, title = {Accurate Masses for Dispersion-Supported Galaxies}, author = {Wolf, Joe and Martinez, Gregory D. and Bullock, James S. and Kaplinghat, Manoj and Geha, Marla and Mu{\~n}oz, Ricardo R. and Simon, Joshua D. and Avedo, Frank F.}, year = {2010}, month = aug, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {406}, number = {2}, pages = {1220--1237}, issn = {0035-8711}, doi = {10.1111/j.1365-2966.2010.16753.x}, urldate = {2021-09-29}, abstract = {We derive an accurate mass estimator for dispersion-supported stellar systems and demonstrate its validity by analysing resolved line-of-sight velocity data for globular clusters, dwarf galaxies and elliptical galaxies. Specifically, by manipulating the spherical Jeans equation we show that the mass enclosed within the 3D deprojected half-light radius r1/2 can be determined with only mild assumptions about the spatial variation of the stellar velocity dispersion anisotropy as long as the projected velocity dispersion profile is fairly flat near the half-light radius, as is typically observed. We find M1/2= 3 G-1{$\langle\sigma$}2los{$\rangle$}r1/2{$\simeq$} 4 G-1{$\langle\sigma$}2los{$\rangle$}Re, where {$\langle\sigma$}2los{$\rangle$} is the luminosity-weighted square of the line-of-sight velocity dispersion and Re is the 2D projected half-light radius. While deceptively familiar in form, this formula is not the virial theorem, which cannot be used to determine accurate masses unless the radial profile of the total mass is known a priori. We utilize this finding to show that all of the Milky Way dwarf spheroidal galaxies (MW dSphs) are consistent with having formed within a halo of a mass of approximately 3 \texttimes{} 109 M{$\odot$}, assuming a {$\Lambda$} cold dark matter cosmology. The faintest MW dSphs seem to have formed in dark matter haloes that are at least as massive as those of the brightest MW dSphs, despite the almost five orders of magnitude spread in luminosity between them. We expand our analysis to the full range of observed dispersion-supported stellar systems and examine their dynamical I-band mass-to-light ratios {$\Upsilon$}I1/2. The {$\Upsilon$}I1/2 versus M1/2 relation for dispersion-supported galaxies follows a U shape, with a broad minimum near {$\Upsilon$}I1/2{$\simeq$} 3 that spans dwarf elliptical galaxies to normal ellipticals, a steep rise to {$\Upsilon$}I1/2{$\simeq$} 3200 for ultra-faint dSphs and a more shallow rise to {$\Upsilon$}I1/2{$\simeq$} 800 for galaxy cluster spheroids.}}
@article{wright_ob_associations_2020, title = {{{OB Associations}} and Their Origins}, author = {Wright, Nicholas J.}, year = {2020}, month = nov, volume = {90}, eprint = {2011.09483}, primaryclass = {astro-ph.SR}, pages = {101549}, doi = {10.1016/j.newar.2020.101549}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,OB Associations,Star clusters,Star formation,Stellar kinematics and dynamics,Young stars}}
@article{wu_using_2021, title = {Using {{Action Space Clustering}} to {{Constrain}} the {{Accretion History}} of {{Milky Way}} like {{Galaxies}}}, author = {Wu, Youjia and Valluri, Monica and Panithanpaisal, Nondh and Sanderson, Robyn E. and Freese, Katherine and Wetzel, Andrew and Sharma, Sanjib}, year = {2021}, month = apr, journal = {arXiv:2104.08185 [astro-ph]}, eprint = {2104.08185}, primaryclass = {astro-ph}, urldate = {2021-04-20}, abstract = {In the currently favored cosmological paradigm galaxies form hierarchically through the accretion of numerous satellite galaxies. Since the satellites are much less massive than the host halo, they occupy a small fraction of the volume in action space defined by the potential of the host halo. Since actions are conserved when the potential of the host halo changes adiabatically, stars from an accreted satellite are expected to remain clustered in action space as the host halo evolves. In this paper, we identify accreted satellites in three Milky Way like disk galaxies from the cosmological baryonic FIRE-2 simulations by tracking satellite galaxies through simulation snapshots. We then try to recover these satellites by applying the cluster analysis algorithm Enlink to the orbital actions of accreted star particles in the present-day snapshot. We define several metrics to quantify the success of the clustering algorithm and use these metrics to identify well-recovered and poorly-recovered satellites. We plot these satellites in the infall time-progenitor mass (or stellar mass) space, and determine the boundaries between the well-recovered and poorly-recovered satellites in these two spaces with classification tree method. The groups found by Enlink are more likely to correspond to a real satellite if they have high significance, a quantity assigned by Enlink. Since cosmological simulations predict that most stellar halos have a population of insitu stars, we test the ability of Enlink to recover satellites when the sample is contaminated by 10-50\% of insitu star particles, and show that most of the satellites well-recovered by Enlink in the absence of insitu stars, stay well-recovered even with 50\% contamination. We thus expect that, in the future, cluster analysis in action space will be useful in upcoming data sets (e.g. Gaia) for identifying accreted satellites in the Milky Way.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\6RRLH79J\\2104.html}}
@article{xu_comprehensive_2015, title = {A {{Comprehensive Survey}} of {{Clustering Algorithms}}}, author = {Xu, Dongkuan and Tian, Yingjie}, year = {2015}, month = jun, journal = {Annals of Data Science}, volume = {2}, number = {2}, pages = {165--193}, issn = {2198-5812}, doi = {10.1007/s40745-015-0040-1}, urldate = {2019-09-04}, abstract = {Data analysis is used as a common method in modern science research, which is across communication science, computer science and biology science. Clustering, as the basic composition of data analysis, plays a significant role. On one hand, many tools for cluster analysis have been created, along with the information increase and subject intersection. On the other hand, each clustering algorithm has its own strengths and weaknesses, due to the complexity of information. In this review paper, we begin at the definition of clustering, take the basic elements involved in the clustering process, such as the distance or similarity measurement and evaluation indicators, into consideration, and analyze the clustering algorithms from two perspectives, the traditional ones and the modern ones. All the discussed clustering algorithms will be compared in detail and comprehensively shown in Appendix Table 22.}, langid = {english}, keywords = {Clustering Algorithm,Read,Review}}
@misc{yaghoobi_ionising_2022, title = {Ionising {{Feedback Effects}} on {{Star Formation}} in {{Globular Clusters}} with {{Multiple Stellar Populations}}}, author = {Yaghoobi, Asiyeh and Rosdahl, Joakim and Calura, Francesco and Khalaj, Pouria and Haghi, Hosein}, year = {2022}, month = oct, number = {arXiv:2210.01136}, eprint = {2210.01136}, primaryclass = {astro-ph, physics:physics}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2210.01136}, urldate = {2022-10-17}, abstract = {Using 3D radiation-hydrodynamical simulations, we study the effects of ionising radiation on the formation of second-generation (SG) stars in Globular Clusters (GCs) with multiple stellar populations. In particular, we focus on massive (\$10\^7 \textbackslash mathrm\{M\}\_\{\textbackslash odot\}\$) and young (40-Myr old) GCs. We consider stellar winds from asymptotic giant branch (AGB) stars, ram pressure, gas accretion onto the cluster, and photoionisation feedback of binary stars. We find that the stellar luminosity is strong enough to warm and ionise the intracluster medium, but it does not lead to a significant gas expulsion. The cluster can thus retain the ejecta of AGB stars and the accreted pristine gas. In addition, efficient cooling occurs in the central region of the cluster within \$50 \textbackslash mathrm\{Myr\}\$ from the formation of first generation stars, leading to the formation of SG stars. Our results indicate that the inclusion of photoionisation does not suppress SG formation, but rather delays it by about \$\textbackslash sim10 \textbackslash mathrm\{Myr\}\$. The time delay depends on the density of the pristine gas, so that a denser medium exhibits a shorter delay in star formation. Moreover, photoionisation leads to a modest decrease in the total SG mass, compared to a model without it.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,Physics - Computational Physics,Physics - Fluid Dynamics}}
@article{yalyalieva_new_2020, title = {A New Look at {{Sco OB1}} Association with {{Gaia DR2}}}, author = {Yalyalieva, L. and Carraro, G. and Vazquez, R. and Rizzo, L. and Glushkova, E. and Costa, E.}, year = {2020}, month = apr, journal = {arXiv:2004.13418 [astro-ph]}, eprint = {2004.13418}, primaryclass = {astro-ph}, urldate = {2020-04-29}, abstract = {We present and discuss photometric optical data in the area of the OB association Sco OB1 covering about 1 squared degree. UBVI photometry is employed in tandem with Gaia DR2 data to investigate the 3 dimensional structure and the star formation history of the region. By combining parallaxes and proper motions we identify 7 physical groups located between the young open cluster NGC 6231 and the bright nebula IC4628. The most prominent group coincides with the sparse open cluster Trumpler 24. We confirm the presence of the intermediate age star cluster VdB-Hagen 202, which is unexpected in this environment, and provide for the first time estimates of its fundamental parameters. After assessing individual groups membership, we derive mean proper motion components, distances, and ages. The seven groups belong to two different families. To the younger family (family I) belong several pre-Main Sequence stars as well. These are evenly spread across the field, and also in front of VdB-Hagen 202. VdB-Hagen 202 and two smaller, slightly detached, groups of similar properties form family II, which do not belong to the association, but are caught in the act of passing through it. As for the younger population, this forms an arc-like structure from the bright nebula IC 4628 down to NGC 6231, as previously found. Moreover, the pre-Main Sequence stars density seems to increase from NGC 6231 northward to Trumpler 24.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{yang_gravitational_2020, title = {Gravitational {{Potential}} from Small-Scale Clustering in Action Space: {{Application}} to {{Gaia DR2}}}, shorttitle = {Gravitational {{Potential}} from Small-Scale Clustering in Action Space}, author = {Yang, Tianyi and Boruah, Supranta Sarma and Afshordi, Niayesh}, year = {2020}, month = apr, journal = {Monthly Notices of the Royal Astronomical Society}, volume = {493}, number = {3}, eprint = {1908.02336}, pages = {3061--3080}, issn = {0035-8711, 1365-2966}, doi = {10.1093/mnras/staa441}, urldate = {2020-08-31}, abstract = {Most measurements of mass in Astronomy that use kinematics of stars or gas rely on assumptions of equilibrium that are often hard to verify. Instead, we develop a novel idea that uses the clustering in action space, as a probe of underlying gravitational potential: the correct potential should maximize small-scale clustering in the action space. We provide a first-principle derivation of likelihood using the two-point correlation function in action space, and test it against simulations of stellar streams. We then apply this method to the 2nd data release of Gaia, and use it to measure the radial force fraction \$f\_h\$ and logarithmic slope \$\textbackslash alpha\$ of dark matter halo profile. We investigate stars within 9-11 kpc and 11.5-15 kpc from Galactic centre, and find \$(f\_h,\textbackslash alpha)= (0.391\textbackslash pm 0.009, 1.835\textbackslash pm 0.092) \$ and \$(0.351\textbackslash pm 0.012,1.687\textbackslash pm 0.079)\$, respectively. We also confirm that the set of parameters that maximize the likelihood function do correspond to the most clustering in the action space. The best-fit circular velocity curve for Milky Way potential is consistent with past measurements (although it is \$\textbackslash sim\$ 5-10\textbackslash\% lower than previous methods that use masers or globular clusters). Our work provides a clear demonstration of the full statistical power that lies in the full phase space information, relieving the need for \{\textbackslash it ad hoc\} assumptions such as virial equilibrium, circular motion, or steam-finding algorithms.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Cosmology and Nongalactic Astrophysics,High Energy Physics - Phenomenology}, file = {C\:\\Users\\Emily\\Zotero\\storage\\7J9BP2PX\\1908.html}}
@article{yasui_low-metallicity_2021, title = {Low-Metallicity {{Young Clusters}} in the {{Outer Galaxy}}. {{III}}. {{Sh}} 2-127}, author = {Yasui, Chikako and Kobayashi, Naoto and Saito, Masao and Izumi, Natsuko and Skidmore, Warren}, year = {2021}, month = feb, journal = {arXiv:2102.05068 [astro-ph]}, eprint = {2102.05068}, primaryclass = {astro-ph}, urldate = {2021-02-15}, abstract = {In deep near-infrared imaging of the low-metallicity (\$\{\textbackslash rm [O/H]\}=-0.7\$ dex) H II region Sh 2-127 (S127) with Subaru/MOIRCS, we detected two young clusters with 413 members (S127A) in a slightly extended H II region and another with 338 members (S127B) in a compact H II region. The limiting magnitude was \$K=21.3\$ mag (10\$\textbackslash sigma\$), corresponding to a mass detection limit of \$\textbackslash sim\$0.2 \$M\_\textbackslash odot\$. These clusters are an order of magnitude larger than previously studied young low-metallicity clusters and larger than the majority of solar neighborhood young clusters. Fits to the K-band luminosity functions indicate very young cluster ages of 0.5 Myr for S127A and 0.1-0.5 Myr for S127B, consistent with the large extinction (up to \$A\_V\textbackslash simeq20\$ mag) from thick molecular clouds and the presence of a compact H II region and class I source candidates, and suggest that the initial mass function (IMF) of the low-metallicity clusters is indistinguishable from typical solar neighborhood IMFs. Disk fractions of \$28\textbackslash\% \textbackslash pm 3\textbackslash\%\$ for S127A and \$40\textbackslash\% \textbackslash pm 4\textbackslash\%\$ for S127B are significantly lower than those of similarly aged solar neighborhood clusters (\$\textbackslash sim\$50\$\textbackslash\%\$-60\$\textbackslash\%\$). The disk fraction for S127B is higher than those of previously studied low-metallicity clusters (\${$<\$$}30 \$\textbackslash\%\$), probably due to S127B's age. This suggests that a large fraction of very young stars in low-metallicity environments have disks, but the disks are lost on a very short timescale. These results are consistent with our previous studies of low-metallicity star-forming regions, suggesting that a solar neighborhood IMF and low disk fraction are typical characteristics for low-metallicity regions, regardless of cluster scales.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M7PJGUAV\\2102.html}}
@misc{ye_revisit_2022, title = {Revisit of Open Clusters {{UPK}} 39, {{UPK}} 41 and {{PHOC}} 39 : A New Binary Open Cluster Found}, shorttitle = {Revisit of Open Clusters {{UPK}} 39, {{UPK}} 41 and {{PHOC}} 39}, author = {Ye, Xianhao and Zhao, Jingkun and Oswalt, Terry D. and Yang, Yong and Zhao, Gang}, year = {2022}, month = jul, number = {arXiv:2207.14229}, eprint = {2207.14229}, primaryclass = {astro-ph}, publisher = {{arXiv}}, doi = {10.48550/arXiv.2207.14229}, urldate = {2022-08-04}, abstract = {We investigate the three open clusters near Aquila Rift cloud, named as UPK 39 (\textbackslash texttt\{c1\} hereafter), UPK 41 (\textbackslash texttt\{c2\} hereafter) in Sim et al. (2019) and PHOC 39 (\textbackslash texttt\{c3\} hereafter) in Hunt \textbackslash\& Reffert (2021), respectively. Using photometric passpands, reddening, and extinction from Gaia DR3, we construct the color-absolute-magnitude diagram (CAMD). Using isochrone fits their ages are estimated as \$6.3\textbackslash pm0.9\$, \$8.1\textbackslash pm1.4\$ and \$21.8\textbackslash pm2.2\$ Myr, respectively. Their proper motions and radial velocities, estimated using data from Gaia and LAMOST are very similar. From their orbits, relative distances among them at different times, kinematics, ages, and metallicities, we conclude that \textbackslash texttt\{c1\} and \textbackslash texttt\{c2\} are primordial binary open cluster, which are likely to have been formed at the same time, and \textbackslash texttt\{c3\} may capture \textbackslash texttt\{c1\}, \textbackslash texttt\{c2\} in the future.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}}
@article{yeh_ruprecht_2019, title = {Ruprecht 147: {{A Paradigm}} of {{Dissolving Star Cluster}}}, shorttitle = {Ruprecht 147}, author = {Yeh, Fu Chi and Carraro, Giovanni and Montalto, Marco and Seleznev, Anton F.}, year = {2019}, month = feb, journal = {The Astronomical Journal}, volume = {157}, number = {3}, pages = {115}, issn = {1538-3881}, doi = {10.3847/1538-3881/aaff6c}, urldate = {2019-11-21}, abstract = {We employed recent Gaia/DR2 data to investigate the dynamical status of the nearby (300 pc), old (2.5 Gyr) open cluster Ruprecht 147. We found prominent leading and trailing tails of stars along the cluster orbit, which demonstrates that Ruprecht 147 is losing stars at fast pace. Star counts indicate the cluster has a core radius of 33.3 arcmin and a tidal radius of 137.5 arcmin. The cluster also possesses an extended corona, which cannot be reproduced by a simple King model. We computed the present-day cluster mass using its luminosity and mass function, and derived an estimate of 234 {$\pm$} 52 M {$\odot$}. We also estimated the cluster original mass using available recipes extracted from N-body simulations obtaining a mass at birth of 50,000 {$\pm$} 6500 M {$\odot$}. Therefore dynamical mass loss, mostly caused by tidal interaction with the Milky Way, reduced the cluster mass by about 99\%. We then conclude that Ruprecht 147 is rapidly dissolving into the general Galactic disk.}, langid = {english}}
@misc{yen_peering_2019, title = {Peering into the {{Milky Way}} Disk: {{Gaia}}'s {{Perspective}} of Our {{Galaxy}}'s {{Open Clusters}}}, author = {Yen, Steffi X.}, year = {19}, month = oct, abstract = {Steffi's thesis!}, file = {C\:\\Users\\Emily\\Zotero\\storage\\GZ5M8RHA\\thesis_steffiyen_28oct19.pdf}}
@article{yen_reanalysis_2018, title = {Reanalysis of Nearby Open Clusters Using {{Gaia DR1}}/{{TGAS}} and {{HSOY}}}, author = {Yen, Steffi X. and Reffert, Sabine and Schilbach, Elena and R{\"o}ser, Siegfried and Kharchenko, Nina V. and Piskunov, Anatoly E.}, year = {2018}, month = jul, journal = {Astronomy \& Astrophysics}, volume = {615}, pages = {A12}, issn = {0004-6361, 1432-0746}, doi = {10.1051/0004-6361/201731905}, urldate = {2019-09-05}, abstract = {\emph{Context{$<$}i/{$>$}. Open clusters have long been used to gain insights into the structure, composition, and evolution of the Galaxy. With the large amount of stellar data available for many clusters in the \emph{Gaia{$<$}i/{$>$} era, new techniques must be developed for analyzing open clusters, as visual inspection of cluster color-magnitude diagrams is no longer feasible. An automatic tool will be required to analyze large samples of open clusters.\emph{Aims{$<$}i/{$>$}. We seek to develop an automatic isochrone-fitting procedure to consistently determine cluster membership and the fundamental cluster parameters.\emph{Methods{$<$}i/{$>$}. Our cluster characterization pipeline first determined cluster membership with precise astrometry, primarily from TGAS and HSOY. With initial cluster members established, isochrones were fitted, using a {$\chi$}\textsuperscript{2{$<$}sup/{$>$} minimization, to the cluster photometry in order to determine cluster mean distances, ages, and reddening. Cluster membership was also refined based on the stellar photometry. We used multiband photometry, which includes ASCC-2.5 \emph{BV{$<$}i/{$>$}, 2MASS \emph{JHK\textsubscript{s{$<$}sub/{$><$}i/{$>$}, and \emph{Gaia G{$<$}i/{$>$} band.\emph{Results{$<$}i/{$>$}. We present parameter estimates for all 24 clusters closer than 333 pc as determined by the Catalogue of Open Cluster Data and the Milky Way Star Clusters catalog. We find that our parameters are consistent to those in the Milky Way Star Clusters catalog.\emph{Conclusions{$<$}i/{$>$}. We demonstrate that it is feasible to develop an automated pipeline that determines cluster parameters and membership reliably. After additional modifications, our pipeline will be able to use \emph{Gaia{$<$}i/{$>$} DR2 as input, leading to better cluster memberships and more accurate cluster parameters for a much larger number of clusters.}}}}}}}}}}}}}, copyright = {\textcopyright{} ESO 2018}, langid = {english}, keywords = {OC Analysis,Read}, file = {C\:\\Users\\Emily\\Zotero\\storage\\M5ZALVA4\\Yen et al. - 2018 - Reanalysis of nearby open clusters using Gaia DR1.pdf;C\:\\Users\\Emily\\Zotero\\storage\\NTP75A53\\Yen et al. - 2018 - Reanalysis of nearby open clusters using Gaia DR1_annotated.pdf;C\:\\Users\\Emily\\Zotero\\storage\\IWZKBP6T\\aa31905-17.html}}
@article{yu_unveiling_2020, title = {Unveiling the {{Hierarchical Structure}} of {{Open Star Clusters}}: The {{Perseus Double Cluster}}}, shorttitle = {Unveiling the {{Hierarchical Structure}} of {{Open Star Clusters}}}, author = {Yu, Heng and Shao, Zheng-Yi and Diaferio, Antonaldo and Li, Lu}, year = {2020}, month = jul, journal = {arXiv:2007.11850 [astro-ph]}, eprint = {2007.11850}, primaryclass = {astro-ph}, urldate = {2020-07-24}, abstract = {We introduce a new kinematic method to investigate the structure of open star clusters. We adopt a hierarchical clustering algorithm that uses the celestial coordinates and the proper motions of the stars in the field of view of the cluster to estimate a proxy of the pairwise binding energy of the stars and arrange them in a binary tree. The cluster substructures and their members are identified by trimming the tree at two thresholds, according to the \$\textbackslash sigma\$-plateau method. Testing the algorithm on 100 mock catalogs shows that, on average, the membership of the identified clusters is \$(91.5\textbackslash pm 3.5)\$\textbackslash\% complete and the fraction of unrelated stars is \$(10.4\textbackslash pm 2.0)\$\textbackslash\%. We apply the algorithm to the stars in the field of view of the Perseus double cluster from the Data Release 2 of Gaia. This approach identifies a single structure, Sub1, that separates into two substructures, Sub1-1 and Sub1-2. These substructures coincide with \$h\$ Per and \$\textbackslash chi\$ Per: the distributions of the proper motions and the color-magnitude diagrams of the members of Sub1-1 and Sub1-2 are fully consistent with those of \$h\$ Per and \$\textbackslash chi\$ Per reported in the literature. These results suggest that our hierarchical clustering algorithm can be a powerful tool to unveil the complex kinematic information of star clusters.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\YBNZTDFF\\2007.html}}
@article{zari_3d_2018, title = {{{3D}} Mapping of Young Stars in the Solar Neighbourhood with {{Gaia DR2}}}, author = {Zari, E. and Hashemi, H. and Brown, A. G. A. and Jardine, K. and {de Zeeuw}, P. T.}, year = {2018}, month = dec, journal = {Astronomy \& Astrophysics}, volume = {620}, pages = {A172}, issn = {0004-6361}, doi = {10.1051/0004-6361/201834150}, urldate = {2022-03-28}, abstract = {We study the three dimensional arrangement of young stars in the solar neighbourhood using the second release of the Gaia mission (Gaia DR2) and we provide a new, original view of the spatial configuration of the star-forming regions within 500 pc of the Sun. By smoothing the star distribution through a Gaussian filter, we construct three dimensional (3D) density maps for early-type stars (upper-main sequence, UMS) and pre-main sequence (PMS) sources. The PMS and the UMS samples are selected through a combination of photometric and astrometric criteria. A side product of the analysis is a 3D, G-band extinction map, which we use to correct our colour-magnitude diagram for extinction and reddening. Both density maps show three prominent structures, Scorpius-Centaurus, Orion, and Vela. The PMS map shows a plethora of lower-mass star-forming regions, such as Taurus, Perseus, Cepheus, Cassiopeia, and Lacerta, which are less visible in the UMS map due to the lack of large numbers of bright, early-type stars. We report the finding of a candidate new open cluster towards l, b {$\sim$} 218.5\textdegree{} , - 2\textdegree, which could be related to the Orion star-forming complex. We estimate ages for the PMS sample and we study the distribution of PMS stars as a function of their age. We find that younger stars cluster in dense, compact clumps, and are surrounded by older sources, whose distribution is instead more diffuse. The youngest groups that we find are mainly located in Scorpius-Centaurus, Orion, Vela, and Taurus. Cepheus, Cassiopeia, and Lacerta are instead more evolved and less numerous. Finally, we find that the 3D density maps show no evidence for the existence of the ring-like structure which is usually referred to as the Gould Belt. {$<$}P /{$>$}The PMS and UMS catalogues are only available at the CDS via anonymous ftp to {$<$}A href="http://cdsarc.u-strasbg.fr/"{$>$}http://cdsarc.u-strasbg.fr{$<$}/A{$>$} (ftp://130.79.128.5) or via {$<$}A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A172"{$>$}http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A172{$<$}/A{$>$}}, langid = {english}}
@inproceedings{zhang_birch_1996, title = {{{BIRCH}}: An Efficient Data Clustering Method for Very Large Databases}, shorttitle = {{{BIRCH}}}, booktitle = {Proceedings of the 1996 {{ACM SIGMOD}} International Conference on {{Management}} of Data}, author = {Zhang, Tian and Ramakrishnan, Raghu and Livny, Miron}, year = {1996}, month = jun, series = {{{SIGMOD}} '96}, pages = {103--114}, publisher = {{Association for Computing Machinery}}, address = {{Montreal, Quebec, Canada}}, doi = {10.1145/233269.233324}, urldate = {2020-07-28}, abstract = {Finding useful patterns in large datasets has attracted considerable interest recently, and one of the most widely studied problems in this area is the identification of clusters, or densely populated regions, in a multi-dimensional dataset. Prior work does not adequately address the problem of large datasets and minimization of I/O costs.This paper presents a data clustering method named BIRCH (Balanced Iterative Reducing and Clustering using Hierarchies), and demonstrates that it is especially suitable for very large databases. BIRCH incrementally and dynamically clusters incoming multi-dimensional metric data points to try to produce the best quality clustering with the available resources (i.e., available memory and time constraints). BIRCH can typically find a good clustering with a single scan of the data, and improve the quality further with a few additional scans. BIRCH is also the first clustering algorithm proposed in the database area to handle "noise" (data points that are not part of the underlying pattern) effectively.We evaluate BIRCH's time/space efficiency, data input order sensitivity, and clustering quality through several experiments. We also present a performance comparisons of BIRCH versus CLARANS, a clustering method proposed recently for large datasets, and show that BIRCH is consistently superior.}, isbn = {978-0-89791-794-0}}
@article{zhang_diagnosing_2019, title = {Diagnosing the {{Stellar Population}} and {{Tidal Structure}} of the {{Blanco1 Star Cluster}}}, author = {Zhang, Yu and Tang, Shih-Yun and Chen, W. P. and Pang, Xiaoying and Liu, J. Z.}, year = {2019}, month = dec, journal = {arXiv:1912.06657 [astro-ph]}, eprint = {1912.06657}, primaryclass = {astro-ph}, urldate = {2020-01-02}, abstract = {We present the stellar population, using \{\textbackslash it Gaia\}\textbackslash,DR2 parallax, kinematics, and photometry, of the young (\$\textbackslash sim 100\$\textasciitilde Myr), nearby (\$\textbackslash sim 230\$\textasciitilde pc) open cluster, Blanco1. A total of 644 member candidates are identified via the unsupervised machine learning method \textbackslash textsc\{StarGO\} to find the clustering in the 5-dimensional position and proper motion parameter (\$X\$, \$Y\$, \$Z\$, \$\textbackslash mu\_\textbackslash alpha \textbackslash cos\textbackslash delta\$, \$\textbackslash mu\_\textbackslash delta\$) space. Within the tidal radius of \$10.0 \textbackslash pm 0.3\$\textasciitilde pc, there are 488 member candidates, 3 times more than those outside. A leading tail and a trailing tail, each of 50--60\textasciitilde pc in the Galactic plane, are found for the first time for this cluster, with stars further from the cluster center streaming away faster, manifest stellar stripping. Blanco1 has a total detected mass of \$285\textbackslash pm32\$\textasciitilde M\$\_\textbackslash odot \$ with a mass function consistent with a slope of \$\textbackslash alpha=1.35\textbackslash pm0.2\$ in the sense of \$dN/dm \textbackslash propto m\^\{-\textbackslash alpha\}\$, in the mass range of 0.25--2.51\textasciitilde M\$\_\textbackslash odot \$, where \$N\$ is the number of members and \$m\$ is stellar mass. A Minimum Spanning Tree (\$\textbackslash Lambda\_\{\textbackslash rm MSR\}\$) analysis shows the cluster to be moderately mass segregated among the most massive members (\$\textbackslash gtrsim 1.4\$\textasciitilde M\$\_\textbackslash odot\$), suggesting an early stage of dynamical disintegration.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics,blanco 1,mass segregation,Read,sc structure,self-organising map,stargo,tidal tails}, file = {C\:\\Users\\Emily\\Zotero\\storage\\WS7AA65L\\1912.html}}
@article{zhang_radial_2021, title = {Radial {{Migration}} from {{Metallicity Gradient}} of {{Open Clusters}} and {{Outliers}}}, author = {Zhang, Haopeng and Chen, Yuqin and Zhao, Gang}, year = {2021}, month = jun, journal = {arXiv:2106.12841 [astro-ph]}, eprint = {2106.12841}, primaryclass = {astro-ph}, urldate = {2021-07-21}, abstract = {Radial migration is an important process in the evolution of the Galactic disk. The metallicity gradient of open clusters and its outliers provide an effective way to probe for this process. In this work, we compile metallicity, age, and kinematic parameters for 225 open clusters and carry out a quantitative analysis of radial migration via the calculated migration distances. Based on clusters with age \${$<$} 0.5\$ Gyr, we obtain the present-day metallicity gradient of \$-0.074 \textbackslash pm 0.007\$ dex/kpc. Along this gradient distributes three sequences, and clusters in the upper, the middle, and the lower groups are found to be old outward-migrators, in-situ clusters, and inward-migrators, respectively. The migration distance increases with age, but its most effective time is probably less than 3 Gyr. The metallicity gradient breaks out at \$R\_g\$ (guiding center radius) \$\textbackslash sim11.5\$ kpc, which is caused by the lack of young open clusters in the outer disk and the presence of old outward-migrators in the upper sequence. It shows that this boundary is related to the different effects of radial migration between the inner and outer disks. We also found many special open clusters in and near the outer disk of \$R {$>$} 11\$ kpc and a steeper metallicity gradient from the inner disk of \$R\_g {$<$} 7\$ kpc, which tells a complicated evolution history of the Galactic disk by different effects of stellar radial migration.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\TD3XLHVZ\\2106.html}}
@article{zhong_exploring_2020, title = {Exploring Open Cluster Properties with {{Gaia}} and {{LAMOST}}}, author = {Zhong, Jing and Chen, Li and Wu, Di and Li, Lu and Bai, Leya and Hou, Jinliang}, year = {2020}, month = jun, journal = {arXiv:2006.06929 [astro-ph]}, eprint = {2006.06929}, primaryclass = {astro-ph}, urldate = {2020-06-15}, abstract = {In Gaia DR2, the unprecedented high-precision level reached in sub-mas for astrometry and mmag for photometry. Using cluster members identified with these astrometry and photometry in Gaia DR2, we can obtain a reliable determination of cluster properties. However, because of the shortcoming of Gaia spectroscopic observation in dealing with densely crowded cluster region, the number of radial velocity and metallicity for cluster member stars from Gaia DR2 is still lacking. In this study, we aim to improve the cluster properties by combining the LAMOST spectra. In particular, we provide the list of cluster members with spectroscopic parameters as an add-value catalog in LAMOST DR5, which can be used to perform detailed study for a better understanding on the stellar properties, by using their spectra and fundamental properties from the host cluster. We cross-matched the spectroscopic catalog in LAMOST DR5 with the identified cluster members in Cantat-Gaudin et al.2018 and then used members with spectroscopic parameters to derive statistical properties of open clusters. We obtained a list of 8811 members with spectroscopic parameters and a catalog of 295 cluster properties. In addition, we study the radial and vertical metallicity gradient and age-metallicity relation with the compiled open clusters as tracers, finding slopes of -0.053\$\textbackslash pm\$0.004 dex kpc\$\^\{-1\}\$, -0.252\$\textbackslash pm\$0.039 dex kpc\$\^\{-1\}\$ and 0.022\$\textbackslash pm\$0.008 dex Gyr\$\^\{-1\}\$, respectively. Both slopes of metallicity distribution relation for young clusters (0.1 Gyr {$<$} Age {$<$} 2 Gyr) and the age-metallicity relation for clusters within 6 Gyr are consistent with literature results. In order to fully study the chemical evolution history in the disk, more spectroscopic observations for old and distant open clusters are needed for further investigation.}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies}, file = {C\:\\Users\\Emily\\Zotero\\storage\\3RFSATGP\\2006.html}}
@article{zhou_galactic_2021, title = {Galactic Open Cluster {{Cepheids}} -- a Census Based on {{Gaia EDR3}}}, author = {Zhou, Xiaoyue and Chen, Xiaodian}, year = {2021}, month = apr, journal = {arXiv:2104.11929 [astro-ph]}, eprint = {2104.11929}, primaryclass = {astro-ph}, urldate = {2021-04-28}, abstract = {In the Gaia era, the membership analysis and parameter determination of open clusters (OCs) are more accurate. We performed a census of OC's classical Cepheids based on Gaia Early Data Release 3 (EDR3) and obtained a sample of 33 OC Cepheids fulfilling the constraints of the spatial position, proper motion, parallax and evolution state. 13 of 33 OC Cepheids are newly discovered. Among them, CM Sct is the first first-crossing Cepheids with direct evidence of evolution. DP Vel is likely a fourth- or fifth-crossing Cepheids. Based on independent distances from OCs, W\_1-band period-luminosity relation of Cepheids is determined with a 3.5\% accuracy: {$<$}MW1{$>$} = -(3.274 +- 0.090) log P - (-2.567 +- 0.080). The Gaia-band period-Wesenheit relation agrees well with Ripepi et al. (2019). A direct period-age relation for fundamental Cepheids are also determined based on OC's age, that is log t = -(0.638 +- 0.063) log P + (8.569 +- 0.057).}, archiveprefix = {arxiv}, keywords = {Astrophysics - Astrophysics of Galaxies,Astrophysics - Solar and Stellar Astrophysics}, file = {C\:\\Users\\Emily\\Zotero\\storage\\WFTXH8BK\\2104.html}}
@article{zonca_healpy_2019, title = {Healpy: Equal Area Pixelization and Spherical Harmonics Transforms for Data on the Sphere in {{Python}}}, shorttitle = {Healpy}, author = {Zonca, Andrea and Singer, Leo P. and Lenz, Daniel and Reinecke, Martin and Rosset, Cyrille and Hivon, Eric and Gorski, Krzysztof M.}, year = {2019}, month = mar, journal = {Journal of Open Source Software}, volume = {4}, number = {35}, pages = {1298}, issn = {2475-9066}, doi = {10.21105/joss.01298}, urldate = {2020-06-24}, abstract = {Zonca et al., (2019). healpy: equal area pixelization and spherical harmonics transforms for data on the sphere in Python. Journal of Open Source Software, 4(35), 1298, https://doi.org/10.21105/joss.01298}, langid = {english}, file = {C\:\\Users\\Emily\\Zotero\\storage\\NNMSK8LH\\joss.html}}
@article{zucker_disconnecting_dots_2022, title = {Disconnecting the {{Dots}}: {{Re-examining}} the {{Nature}} of {{Stellar}} "{{Strings}}" in the {{Milky Way}}}, shorttitle = {Disconnecting the {{Dots}}}, author = {Zucker, Catherine and Peek, J. E. G. and Loebman, Sarah}, year = {2022}, month = sep, journal = {The Astrophysical Journal}, volume = {936}, pages = {160}, issn = {0004-637X}, doi = {10.3847/1538-4357/ac898c}, urldate = {2022-12-09}, abstract = {Recent analyses of Gaia data have resulted in the identification of new stellar structures, including a new class of extended stellar filaments called stellar "strings," first proposed by Kounkel \& Covey. We explore the spatial, kinematic, and chemical composition of strings to demonstrate that these newfound structures are largely inconsistent with being physical objects whose members share a common origin. Examining the 3D spatial distribution of string members, we find that the spatial dispersion around the claimed string spine does not improve in the latest Gaia DR3 data release-despite tangible gains in the signal-to-noise ratio of the parallax measurements-counter to expectations of a bona fide structure. Using the radial velocity dispersion of the strings (averaging \$\{\textbackslash sigma \}\_\{\{V\}\_\{r\}\}=16\textbackslash,\textbackslash mathrm\{km\}\textbackslash,\{\{\textbackslash rm\{s\}\}\}\^\{-1\}\$ ) to estimate their virial masses, we find that all strings are gravitationally unbound. Given the finding that the strings are dispersing, the reported stellar ages of the strings are typically 120\texttimes{} larger than their measured dispersal times. Finally, we validate prior work that stellar strings are more chemically homogeneous than their local field stars but show it is possible to obtain the same signatures of chemical homogeneity by drawing random samples of stars from spatially, temporally, and kinematically unrelated open clusters. Our results show that while some strings may be composed of real substructures, there is no consistent evidence for larger string-like connections over the sample. These results underscore the need for caution in over-interpreting the significance of these strings and their role in understanding the star formation history of the Milky Way.}, keywords = {1054,1567,1596,842,Astrophysics - Astrophysics of Galaxies,Interstellar filaments,Milky Way Galaxy,Star clusters,Stellar dynamics}, annotation = {ADS Bibcode: 2022ApJ...936..160Z}}