The evolution of cluster dwarfs

Abstract

We summarize the results from analyzing six clusters of galaxies at 0.14 < z < 0.40 observed with the Hubble Space Telescope Advanced Camera for Surveys. We derive deep composite luminosity functions in B, g, V, r, i, and z down to absolute magnitude of ∼ -14 + 5 log h mag. The luminosity functions are fitted by a single Schechter function with M_BgVriz^* = -19.8, -20.9, -21.9, -22.0, -21.7, and -22.3 mag, and α ∼ -1.3 for all bands. The data suggests red sequence dominates the luminosity function down to ≥ 6 mag below L_*, the dwarf spheroidals regime. Hence, at least at z ∼ 0.3, the red sequence is well established and galaxies down to dwarf spheroidals are assembled within these clusters. We do not detect the faint-end upturn (M > -16) that is observed in lower redshift clusters. If this is real, the faint-end population has originated since z=0.3.