A sample of 1959 massive galaxy clusters at high redshifts

Abstract

We identify a sample of 1959 massive clusters of galaxies in the redshift range of 0.7<z<1.0 from the survey data of Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE). These clusters are recognized as the overdensity regions around the SDSS luminous red galaxies, having a richness greater than 15 or an equivalent mass M_{500} \ge 2.5*10^{14}M_{\odot}. Among them, 1505 clusters are identified for the first time, which significantly enlarge the number of high-redshift clusters of z>0.75. By comparing them with clusters at lower redshifts, we confirm that richer clusters host more luminous brightest cluster galaxies (BCGs) also at high redshifts, and that the fraction of blue galaxies is larger in clusters at higher redshifts. A small fraction of BCGs show ongoing star formation or active nuclei. The number density profile of member galaxies in stacked samples of clusters shows no significant redshift evolution.