The Richness-Dependent Cluster Correlation Function: Early SDSS Data

Preprint
Publisher Website
Google Scholar
Abstract
The cluster correlation function and its richness dependence are determined from over 10^3 clusters of galaxies -- the largest sample of clusters studied so far -- found in 400 deg^2 of Sloan Digital Sky Survey early data. The results are compared with previous samples of optically and X-ray selected clusters. The richness-dependent correlation function increases monotonically from an average correlation scale of ~12 h^{-1} Mpc for poor clusters with a mean separation of ~20 h^{-1} Mpc, to a correlation scale of ~20-25 h^{-1} Mpc for the richer, more massive clusters with mean separations of ~60-90 h^{-1} Mpc. X-ray selected clusters seem to suggest slightly stronger correlations than optically selected clusters but the results are consistent within 2-sigma. The results are compared with large-scale cosmological simulations. The observed richness-dependent cluster correlation function is well represented by the standard flat LCDM model (\Omega_m~=0.3, h~=0.7), and, as expected, is inconsistent with the considerably weaker correlations predicted by \Omega_m=1 models. We derive an analytic relation for the correlation scale versus cluster mean separation, r_0 - d, that best describes the LCDM prediction and the observations: r_0 (h^{-1} Mpc) = 2.6 * d (h^{-1} Mpc) ^0.5 (for d~= 20 - 90 h^{-1} Mpc). Data from the complete Sloan Digital Sky Survey, when available, will greatly enhance the accuracy of the results and will allow a more precise determination of cosmological parameters.

This publication has 0 references indexed in Scilit: