Antlia: an outskirt Local Group Galaxy

Abstract

Deep (I,V-I) and (I,B-I) color-magnitude diagrams (CMDs) of the Antlia dwarf galaxy, based on Science Verification (SV) data collected with the FORS I camera on the ESO Very Large Telescope (VLT) are presented. By adopting the new calibration of the Tip of the Red Giant Branch (TRGB) provided by Salaris & Cassisi (1998) we estimated that the Antlia distance modulus is (m-M)o=25.98 with an error of 0.10 mag. We suggest an improvement of the classical TRGB method based on infrared H and K magnitudes of TRGB stars. Such a method should overcome the well-known limit of the "classical" TRGB method when dealing with metal-rich stellar populations.