Primordial Feature at the Scale of Superclusters of Galaxies

Abstract

We investigate a spatially-flat cold dark matter model (with the matter density parameter $Ω_m=0.3$) with a primordial feature in the initial power spectrum. We assume that there is a bump in the power spectrum of density fluctuations at wavelengths $λ\sim 30-60h^{-1}$Mpc, which correspond to the scale of superclusters of galaxies. There are indications for such a feature in the power spectra derived from redshift surveys and also in the power spectra derived from peculiar velocities of galaxies. We study the mass function of clusters of galaxies, the power spectrum of the CMB temperature fluctuations, the rms bulk velocity and the rms peculiar velocity of clusters of galaxies. The baryon density is assumed to be consistent with the BBN value. We show that with an appropriately chosen feature in the power spectrum of density fluctuations at the scale of superclusters, the mass function of clusters, the CMB power spectrum and peculiar velocities are in good agreement with the observed data.