Physical properties of star clusters in the outer LMC as observed by the Dark Energy Survey

Abstract

The Large Magellanic Cloud (LMC) harbors a rich and diverse system of star clusters, whose ages, chemical abundances, and positions provide information about the LMC history of star formation. We use Science Verification imaging data from the Dark Energy Survey to increase the census of known star clusters in the outer LMC and to derive physical parameters for a large sample of such objects using a spatially and photometrically homogeneous data set. Our sample contains 255 visually identified cluster candidates, of which 109 were not listed in any previous catalog. We quantify the crowding effect for the stellar sample produced by the DES Data Management pipeline and conclude that the stellar completeness is < 10% inside typical LMC cluster cores. We therefore develop a pipeline to sample and measure stellar magnitudes and positions around the cluster candidates using DAOPHOT. We also implement a maximum-likelihood method to fit individual density profiles and colour-magnitude diagrams. For 117 (from a total of 255) of the cluster candidates (28 uncatalogued clusters), we obtain reliable ages, metallicities, distance moduli and structural parameters, confirming their nature as physical systems. The distribution of cluster metallicities shows a radial dependence, with no clusters more metal-rich than [Fe/H] ~ -0.7 beyond 8 kpc from the LMC center. The age distribution has two peaks at ~ 1.2 Gyr and ~ 2.7 Gyr.

41 pages, 16 figures, 1 appendix

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Cited by in corpus (23)

• The Dark Energy Survey: more than dark energy - an overview
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• SMASHing the LMC: A Tidally-induced Warp in the Outer LMC and a Large-scale Reddening Map
• A Deep View of a Fossil Relic in the Galactic Bulge: The Globular Cluster HP1
• The VISCACHA survey - I. Overview and First Results
• Discovery of an Ultra-Faint Stellar System near the Magellanic Clouds with the DECam Local Volume Exploration (DELVE) Survey
• SMASH 1: a very faint globular cluster disrupting in the outer reaches of the LMC?
• Star cluster formation history along the minor axis of the Large Magellanic Cloud
• The VISCACHA survey -- II. Structure of star clusters in the Magellanic Clouds periphery
• Deep SOAR follow-up photometry of two Milky Way outer-halo companions discovered with Dark Energy Survey
• Metallicities and ages for star clusters and their surrounding fields in the Large Magellanic Cloud
• A search for star clusters in the outskirts of the Large Magellanic Cloud: indication of clusters in the age gap
• Young stars in the periphery of the Large Magellanic Cloud
• Stellar cluster candidates discovered in the Magellanic System
• Kinematic Structure of the Large Magellanic Cloud Globular Cluster System from Gaia eDR3 and Hubble Space Telescope Proper Motions
• Shape of the outer stellar warp in the Large Magellanic Cloud disk
• A likely runaway star cluster in the outer disc of the Large Magellanic Cloud
• KMHK 1762: Another star cluster in the Large Magellanic Cloud age gap
• Strömgren metallicities for intermediate-age and old star clusters
• RR Lyrae Stars in Intermediate-age Magellanic Clusters: Membership Probabilities and Delay Time Distribution
• The YMCA (Yes, Magellanic Clouds Again) survey: probing the outer regions of the Magellanic system with VST
• On the Age Calibration of Open Clusters using Red Clump Stars