TY - JOUR
T1 - A Novel Method to Automatically Detect and Measure the Ages of Star Clusters in Nearby Galaxies
T2 - Application to the Large Magellanic Cloud
AU - Bitsakis, T.
AU - Bonfini, P.
AU - González-Lópezlira, R. A.
AU - Ramírez-Siordia, V. H.
AU - Bruzual, G.
AU - Charlot, S.
AU - Maravelias, G.
AU - Zaritsky, D.
N1 - Funding Information:
The authors would like to thank Dr. A. Piatti for insightful comments that helped improve this paper, and Dr. H. Oti for helping with the data acquisition in the initial stages of this investigation. The authors wish to thank the anonymous referee for her/his thorough review and valuable comments. T.B. would like to acknowledge support from the CONACyT Research Fellowships program. We gratefully acknowledge support from the program for basic research of CONACyT through grant number 252364. G.M. acknowledges support from CONICYT, Programa de Astronomía/PCI, FONDO ALMA 2014, Proyecto No 31140024, and GA ČR under grant number 14-21373S. R.A.G.L. thanks DGAPA, UNAM, for support through the PASPA program. G.B. acknowledges support for this work from UNAM through grant PAPIIT IG100115. This research made use of TOPCAT, an interactive graphical viewer and editor for tabular data. IRAF is distributed by the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under cooperative agreement with the National Science Foundation.
PY - 2017/8/10
Y1 - 2017/8/10
N2 - We present our new, fully automated method to detect and measure the ages of star clusters in nearby galaxies, where individual stars can be resolved. The method relies purely on statistical analysis of observations and Monte-Carlo simulations to define stellar overdensities in the data. It decontaminates the cluster color-magnitude diagrams and, using a revised version of the Bayesian isochrone fitting code of Ramírez-Siordia et al., estimates the ages of the clusters. Comparisons of our estimates with those from other surveys show the superiority of our method to extract and measure the ages of star clusters, even in the most crowded fields. An application of our method is shown for the high-resolution, multiband imaging of the Large Magellanic Cloud. We detect 4850 clusters in the 7 deg2 we surveyed, 3451 of which have not been reported before. Our findings suggest multiple epochs of star cluster formation, with the most probable occurring ∼310 Myr ago. Several of these events are consistent with the epochs of the interactions among the Large and Small Magellanic Clouds, and the Galaxy, as predicted by N-body numerical simulations. Finally, the spatially resolved star cluster formation history may suggest an inside-out cluster formation scenario throughout the LMC, for the past 1 Gyr.
AB - We present our new, fully automated method to detect and measure the ages of star clusters in nearby galaxies, where individual stars can be resolved. The method relies purely on statistical analysis of observations and Monte-Carlo simulations to define stellar overdensities in the data. It decontaminates the cluster color-magnitude diagrams and, using a revised version of the Bayesian isochrone fitting code of Ramírez-Siordia et al., estimates the ages of the clusters. Comparisons of our estimates with those from other surveys show the superiority of our method to extract and measure the ages of star clusters, even in the most crowded fields. An application of our method is shown for the high-resolution, multiband imaging of the Large Magellanic Cloud. We detect 4850 clusters in the 7 deg2 we surveyed, 3451 of which have not been reported before. Our findings suggest multiple epochs of star cluster formation, with the most probable occurring ∼310 Myr ago. Several of these events are consistent with the epochs of the interactions among the Large and Small Magellanic Clouds, and the Galaxy, as predicted by N-body numerical simulations. Finally, the spatially resolved star cluster formation history may suggest an inside-out cluster formation scenario throughout the LMC, for the past 1 Gyr.
KW - Magellanic Clouds
KW - catalogs
KW - galaxies: star clusters: general
KW - methods: statistical
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U2 - 10.3847/1538-4357/aa8090
DO - 10.3847/1538-4357/aa8090
M3 - Article
AN - SCOPUS:85028314763
VL - 845
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 56
ER -