The Power Spectrum of Rich Clusters on Near Gigaparsec Scales

Abstract

Recently, there have been numerous analyses of the redshift space power spectrum of rich clusters of galaxies. Some of these analyses indicate a &#34;bump&#34; in the Abell/ACO cluster power spectrum around k= 0.05hMpc^-1. Such a feature in the power spectrum excludes most standard formation models and indicates possible periodicity in the distribution of large-scale structure. However, the data used in detecting this peak include clusters with estimated redshifts and/or clusters outside of Abell&#39;s (1958) statistical sample, i.e. R=0 clusters. Here, we present estimations of the redshift-space power spectrum for a newly expanded sample of 637 R >= 1 Abell/ACO clusters which has a constant number density to z = 0.10 in the Southern Hemisphere and a nearly constant number density to z = 0.14 in the Northern Hemisphere. The volume sampled, \~10^8h^{-3}Mpc^{3}, is large enough to accurately calculate the power per mode to scales approaching 10^3h^{-1}Mpc. We find the shape of the power spectrum is is a power-law on scales 0.02 <= k <= 0.10hMpc^{-1}, with enhanced power over less rare clusters, such as APM clusters. The slope of this power-law is n= -1.4. The power spectrum is essentially featureless, although we do see a dip near $k = 0.04h$Mpc$^{-1}$ which cannot be considered statistically significant based on this data alone. We do not detect a narrow peak at $k \sim 0.05h$Mpc$^{-1}$ and there is no evidence for a turn-over in the power spectrum as has been previously reported. We compare the shape of the Abell/ACO rich cluster power spectrum to various linear models.