Galaxy Cluster Correlation Function to z ~ 1.5 in the IRAC Shallow Cluster Survey

Abstract

We present the galaxy cluster autocorrelation function of 277 galaxy cluster candidates with 0.25 ≤ z ≤ 1.5 in a 7 deg2area of the IRAC Shallow Cluster Survey. We find strong clustering throughout our galaxy cluster sample, as expected for these massive structures. Specifically, at (z) = 0.5 we find a correlation length of ro= 17.40-3.98-3.98h-lMpc, in excellent agreement with the Las Campanas Distant Cluster Survey, the only other nonlocal measurement. At higher redshift, (z) = 1, we find that strong clustering persists, with a correlation length of r0 = 19.14-5.65-4.56h-lMpc. A comparison with high-resolution cosmological simulations indicates these are clusters with halo masses of ∼1014MΟ, a result supported by estimates of dynamical mass for a subset of the sample. In a stable clustering picture, these clusters will evolve into massive (1015MΟ) clusters by the present day. cosmology: observations -galaxies: clusters: general -large-scale structure of universe Online material: color figure © 2007. The American Astronomi cal Society, All rights reserved.