The red-sequence luminosity function in massive intermediate-redshift galaxy clusters

Abstract

We measure the rest-frame B-band luminosity function of red-sequence galaxies of five intermediate-redshift (0.5 < z < 0.9), high-mass (σ>950 km s-1) clusters. Cluster galaxies are identified through photometric redshifts based on imaging in seven bands (five broad and two narrow) using the WIYN 3.5 m telescope. The luminosity functions (LFs) are well-fit down to M*B + 3 for all of the clusters out to a radius of R 200. For comparison, the LFs for a sample of 59 low-redshift clusters selected from the Sloan Digital Sky Survey are measured as well. There is a brightening trend (M*B increases by 0.7 mag at z = 0.75) with redshift comparable to what is seen in the field for similarly defined galaxies, although there is a hint that the cluster red-sequence brightening is more rapid in the past (z > 0.5), and relatively shallow at more recent times. Contrary to other claims, we find little evidence for evolution of the faint-end slope. Previous indications of evolution may be due to limitations in measurement technique, bias in the sample selection, and cluster-to-cluster variation. As seen in both the low- and high-redshift samples, a significant amount of variation in LF parameters α and M* exists between individual clusters. © 2009. The American Astronomical Society. All rights reserved..