A comparison of ACO and Abell catalogs of clusters
R. Scaramella, G. Zamorani, Giampaolo Vettolani, Guido L. Chincarini · The Astronomical Journal · 1991
We present the results of a statistical analysis of the ACO and Abell catalogs of clusters of galaxies. For both catalogs new estimates of distances, surface, and radial densities are derived. In particular, for the ACO catalog we find that the derived radial-density distribution (including R = 0 clusters) is consistent with a uniform density of clusters up to at least 350h^-1^ Mpc. Moreover, within this distance the ACO data do not show any significant deficiency of R = 0 clusters. In both catalogs we also study the effects of large angular gradients and derive maximum- likelihood estimates for the interesting parameters (i.e., galactic latitude and zenithal dependencies). The ACO catalog appears to be more complete, with a larger volume density of clusters than the Abell catalog. After corrections for large-scale gradients the estimated volume densities of R>=l clusters are (12.5 +/- 1.1) and (8.7 +/- 1.0) in units of 10^6^ (h^-1^ Mpc)^-3^ for the ACO and Abell clusters, respectively. Both these values are higher than the value usually used in the literature for the volume density of rich clusters. Differences and agreements found with the results obtained by other authors from similar studies are also discussed.