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S. M. Hansen (Univ. of Michigan), J. Annis (FNAL), T. Goto (Carnegie Mellon), R. S. J. Kim (Johns Hopkins), A. Kimball, T. A. McKay, E. S. Sheldon (Univ. of Michigan)
We present the application of statistical background subtraction techniques for deriving the luminosity function and halo occupation distribution function of galaxy clusters in the SDSS early data release. The sample of several hundred clusters and thousands of groups are identified in the data using three different algorithms. Cluster members are identified statistically by measuring the excess galaxy population in cluster fields compared to control fields. The large area of sky covered by the SDSS allows us to examine clusters to large radii, and provides ample blank sky, allowing us to compute errors without relying on estimates of the background variance. We compute the luminosity function for clusters with z < 0.3 in the range -23 < M < -16 (for h=1) for g*, r*, and i* bands for clusters and groups found in each of the three catalogs. The resulting luminosity functions are well fit by a Schechter function, but vary among the cluster samples. We show that the derived luminosity function is systematically affected by selection effects, and compare the range of observed luminosity functions with that of the field. We also present the halo occupation distribution function for these clusters.
The author(s) of this abstract have provided an email address for comments about the abstract: smonk@umich.edu