Ultra-Compact Dwarfs (UCDs) in the Antlia cluster

JUAN PABLO CASO; LILIA P. BASSINO; TOM RICHTLER; ANALIA V SMITH CASTELLI; FAVIO FAIFER; SERGIO A. CELONE; MATIAS GÓMEZ

Santiago

Workshop; Dynamics of Low-Mass Stellar Systems: From Star Clusters to Dwarf Galaxies; 2011

European Southern Observatory

The first results in the search for UCDs in the central region of the Antlia cluster are presented, including the confirmation as members of a sample of objects (CasoJ.P.,PhDThesis,inprep).The observational material used consists of wide field CCDimages (36’x36’) from the Cerro Tololo Inter-American Observatory (CTIO,Chile), obtained with the MOSAIC camera in the Washington photometric system; CCD images from Paranal Observatory (ESO), obtained with the camera FORS1 (VLT) of four fields located in the central region of the cluster; and spectra of several fields around NGC3258 and NGC3268, obtained with GMOS (Gemini South, Chile).The UCD candidates had been selected from the point sources found in the MOSAIC field, taking into account their colours (C-T1) and magnitudes (T1).Radial velocities were measured from the GMOS spectra, resulting in the confirmation as cluster members of seven objects with brightness in the range corresponding to UCDs and eight in the range of globular clusters (GCs).