The cluster-cluster correlation in hybrid models

Using N-body simulations, we have calculated the two-point correlation functions of the clusters of galaxies (ξ_cc_) in a set of hybrid (CDM + HDM + baryon) models. The galaxies are identified as density peaks above certain thresholds, to match the observed two-point correlation function of galaxies on scales <~10 h^-1^ Mpc. The clusters of galaxies are identified such that their number density is the same as that of Abell clusters. It is found that both the coherence length (the largest scale where ξ_cc_ remains positive) and the amplitude of ξ_cc_ increase systematically with the power of the initial density spectrum on large scales. For one model in which the power on large scales is sufficient to match the two-point angular correlation function of galaxies of the APM survey, ξ_cc_has a correlation length r_0_ = 23.0 +/- 0.9 h^-1^ Mpc and remains positive for r <~70 h^-1^ Mpc with a weak dependence on the richness of clusters, in good agreement with observations. Our results suggest that the observed large correlation length of Abell clusters, which is sometimes considered to be due to contaminations, should be expected in models which have enough power to explain the recent observations of galaxy clustering and motions on large scales.