Cluster Abundance from Perturbation Spectra with Broken Scale Invariance

Abstract

A double inflationary model with enhanced power at large scales --- Broken Scale Invariant perturbations (BSI) --- leads to a promising scenario for the formation of large-scale structure. We use high-resolution PM simulations with a model for the thermodynamic evolution of baryons. Galactic halos are identified as peaks in the distribution of mass points which had time to cool providing a physical biasing mechanism. The clustering properties of galactic halos are in agreement with both small-scale and large-scale characteristics of the galaxy distribution, as variances of counts in cells, 'galaxy' correlation functions, 'cluster' abundances and 'cluster-cluster' correlation functions, and velocity dispersions at small scales.