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Description
Clusters of galaxies in most of the previous catalogs have redshifts z<=0.3. Using the photometric redshifts of galaxies from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6), we identify 39716 clusters in the redshift range 0.05<z<0.6 with more than eight luminous (M_r_<=-21) member galaxies. Cluster redshifts are estimated accurately with an uncertainty of less than 0.022. The contamination rate of member galaxies is found to be roughly 20%, and the completeness of member galaxy detection reaches ~90%. Monte Carlo simulations show that the cluster detection rate is more than 90% for massive (M_200_>2x10^14^M_{sun}_) clusters of z<=0.42. The false detection rate is ~5%. We obtain the richness, the summed luminosity, and the gross galaxy number within the determined radius for identified clusters. They are tightly related to the X-ray luminosity and temperature of clusters. Cluster mass is related to the richness and summed luminosity with M_200_{prop.to}R^1.90+/-0.04^ and M_200_{prop.to}L^1.64+/-0.03^_r_, respectively. In addition, 790 new candidates of X-ray clusters are found by cross-identification of our clusters with the source list of the ROSAT X-ray survey.
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