An Updated SMC and Magellanic Bridge Catalog of Star Clusters, Associations and Related Objects

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 $\\Lambda$ 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.