Galaxy Cluster Correlation Function to Z ∼ 1.5 in the Irac Shallow Cluster Survey

We present the galaxy cluster autocorrelation function of 277 galaxy cluster candidates with 0.25 ≤ z ≤ 1.5 in a 7 deg2 area 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 r0 = 17.40+3.98 −3.10 h −1 Mpc, in excellent agreement with the Las Campanas Distant Cluster Survey, the only other non–local measurement. At higher redshift, 〈z〉 = 1, we find that strong clustering persists, with a correlation length of r0 = 19.14+5.65 −4.56 h −1 Mpc. A comparison with high resolution cosmological simulations indicates these are clusters with halo masses of ∼ 10M⊙, 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 (10M⊙) clusters by the present day. Subject headings: galaxies: clusters: general — cosmology: observations — large–scale structure of the universe