Dwarf galaxies in four rich clusters with 0.02 < z < 0.14

Abstract

Deep measurements are presented of four rich clusters of galaxies: Abell 1367 (z=0.022), Abell 2199 (z=0.030), Abell 1795 (z=0.063), and Abell 1146 (z=0.141). All clusters have an excess of galaxies at faint magnitudes above blank sky fields. We correct for background contamination and measure the luminosity function of these galaxies in each cluster, and then combine these luminosity functions to get better statistics. The resultant combined luminosity function is rising at faint magnitudes, with a logarithmic slope -1.5 < α< -1.2 for -18 < M_B < -13 and -19 < M_R < -15. This is similar to what has been observed independently in the Coma cluster. The colours of these faint galaxies suggest that they are dwarf spheroidals.