The richness dependence of galaxy cluster correlations: results from a redshift survey of rich APM clusters

Open Access
Publisher Website
Google Scholar
Abstract
We analyse the spatial clustering properties of a new catalogue of very rich galaxy clusters with newly measured redshifts selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell richness class ≥ 1 clusters, but selected using an objective algorithm from a catalogue demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function ξ cc(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best-fitting slope and amplitude of a power-law fit to ξcc(r), and to estimate the correlation length r0 [the value of r at which ξ cc(r) is equal to unity]. For clusters with a mean space density of 1.6 × 10−6h3 Mpc−3 (equivalent to the space density of Abell richness ≥ 2 clusters), we find r0 = 21.3 −9.3+11.1h−1 Mpc (95 per cent confidence limits). This is consistent with the weak richness dependence of ξcc(r) expected in Gaussian models of structure formation. In particular, the amplitude of ξcc(r) at all richnesses matches that of ξcc(r) for clusters selected in N-body simulations of a low-density cold dark matter model.
All Related Versions

This publication has 0 references indexed in Scilit: