Author(s): , , , ,
Institution(s): 1. National Research Council of Canada, 2. Peking University, 3. Shanghai Jiao Tong University
Ultra Compact Dwarf galaxies (UCDs) are regarded as one of the transition objects between star clusters and galaxies. Their possible origins are massive star clusters, stripped galactic nuclei, or primordial compact galaxies. Recent studies reveal that luminous UCDs may originate from tidally-stripped nucleated galaxies, but there is still a possibility of the star cluster origin scenario for less luminous UCDs.
We present a multi-wavelength study of about one hundred spectroscopically confirmed UCDs from the Next Generation Virgo cluster Survey (NGVS). We obtain UV and IR data for the UCDs from GALEX archive and WISE surveys, respectively. We compare UV-optical and optical-IR colors of the UCDs with those of globular clusters. Ages, metallicities, and masses of UCDs are estimated by comparing their SEDs with theoretical simple stellar population models. This multi-wavelength study provides the largest sample of information for the stellar populations of UCDs. Possible scenarios for UCD formation will be discussed.