Galaxy Luminosity Functions from Deep Spectroscopic Samples of Rich Clusters

Using a new spectroscopic sample and methods accounting for spectroscopicsampling fractions that vary in magnitude and surface brightness, we presentR-band galaxy luminosity functions (GLFs) for six nearby galaxy clusters withredshifts 4000 < cz < 20000 km/s and velocity dispersions 700 < sigma < 1250km/s. In the case of the nearest cluster, Abell 1060, our sample extends toM_R=-14 (7 magnitudes below M*), making this the deepest spectroscopicdetermination of the cluster GLF to date. Our methods also yield composite GLFsfor cluster and field galaxies to M_R=-17 (M*+4), including the GLFs ofsubsamples of star forming and quiescent galaxies. The composite GLFs areconsistent with Schechter functions (M*_R=-21.14^{+0.17}_{-0.17},alpha=-1.21^{+0.08}_{-0.07} for the clusters, M*_R=-21.15^{+0.16}_{-0.16},alpha=-1.28^{+0.12}_{-0.11} for the field). All six cluster samples areindividually consistent with the composite GLF down to their respectiveabsolute magnitude limits, but the GLF of the quiescent population in clustersis not universal. There are also significant variations in the GLF of quiescentgalaxies between the field and clusters that can be described as a steepeningof the faint end slope. The overall GLF in clusters is consistent with that offield galaxies, except for the most luminous tip, which is enhanced in clustersversus the field. The star formation properties of giant galaxies are morestrongly correlated with the environment than those of fainter galaxies.Comment: 53 pages, 8 figures, 1 ASCII table; accepted for publication in Ap