A GMBCG Galaxy Cluster Catalog of 55 , 437 Rich Clusters from SDSS DR 7

We present a large catalog of optically selected galaxy clusters from the application of a new Gaussian Mixture Brightest Cluster Galaxy (GMBCG) algorithm to SDSS Data Release 7 data. The algorithm detects clusters by identifying the red sequence plus Brightest Cluster Galaxy (BCG) feature, which is unique for galaxy clusters and does not exist among field galaxies. Red sequence clustering in color space is detected using an Error Corrected Gaussian Mixture Model. We run GMBCG on 8240 square degrees of photometric data from SDSS DR7 to assemble the largest ever optical galaxy cluster catalog, consisting of over 55,000 rich clusters across the redshift range from 0.1 < z < 0.55. We present Monte Carlo tests of completeness and purity and perform cross-matching with X-ray clusters and with the maxBCG sample at low redshift. These tests indicate high completeness and purity across the full redshift range for clusters with 15 or more members. The catalog can be accessed from the following website: http://home.fnal.gov/~jghao/gmbcg_sdss_catalog.html. Subject headings: Galaxies: clusters, CatalogCosmology: observations Methods: Data analysis, Gaussian Mixture Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 Department of Physics, University of Michigan, Ann Arbor, MI 48109 Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 TABASGO Fellow, Physics Department, University of California at Santa Barbara, Santa Barbara, CA 93106 Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Einstein and KICP Fellow, Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, IL 60637 Kavli Institute for Particle Astrophysics & Cosmology, Physics Department, and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 Department of Physics, California Institute of Technology, Pasadena CA 91125 Department of Physics, The University of Chicago, Chicago, IL 60637 Brookhaven National Laboratory, Upton, New York 11973 KIPAC, SLAC National Accelerator Laboratory, Menlo Park, CA 94025 SLAC-PUB-14296