The APM Cluster Redshift Survey

Abstract

Catalogues of rich galaxy clusters selected from the APM Galaxy Survey show that the amplitude of the cluster autocorrelation function, w _cc (θ), depends strongly on the algorithm used to identify the clusters. However, by using a small effective radius to estimate the cluster richness and distance parameters we find that the catalogues are more stable and the resulting w _cc (θ) measurements less sensitive to varying other selection parameters. We have completed a redshift survey of the richest ∼ 200 clusters and find that the amplitude of the three dimensional clustering corresponds to s ₀ ∼ 13 h^-1Mpc, consistent with the amplitude of w _cc (θ). For scales s ≲ 15 h^-1Mpc, the amplitude is compatible with the predictions of the standard CDM model, but on scales s ≲ 20–30 h^-1 Mpc our measurements suggest more large-scale clustering than predicted.