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We present new estimates of the spatial two-point correlation function of rich clusters of galaxies selected from the APM Galaxy Survey. We have measured redshifts for a sample of 364 clusters out to a depth of | 450 h^-1 Mpc^1|. The clusters have a mean space density of |n = 3. 4 10^-5 h^3 Mpc^-3|. The two-point correlation function in redshift space, ξcc (s), for this sample is equal to unity at a pair separation of |r₀ = 14. 3 2. 35 h^-1 Mpc| (2σ errors), consistent with our earlier results from a smaller sample. The new observations provide an accurate determination of the shape of ξcc to pair separations of about 50 h–1 Mpc. Our results show that ξcc has a higher amplitude than expected according to the standard Ω = 1 cold dark matter (CDM) model on spatial scales of 2 ≲ s ≲ 50 h–1 Mpc, but are in good agreement with scale-invariant fluctuations in either a low-density CDM model or a critical-density universe made up of a mixture of hot and cold dark matter. Our results provide strong constraints on so-called ‘cooperative’ models of galaxy formation, in which the galaxy formation process introduces large-scale structure into the galaxy distribution.
Dalton et al. (Tue,) studied this question.