Secondary Cosmic Microwave Background Anisotropies from Cosmological Reionization

Abstract

We use numerical simulation of cosmological reionization to calculate the secondary CMB anisotropies in a representative flat low density cosmological model. We show that the kinetic Sunyaev-Zel'dovich effect (scattering off of moving electrons in the ionized intergalactic medium) is dominated by the nonlinear hydrodynamic and gravitational evolution of the density and velocity fields, rather than the detailed distribution of the ionization fraction (``patchy reionization'') on all angular scales. Combining our results with the recent calculation of secondary CMB anisotropies by Springel et al., we are able to accurately predict the power spectrum of the kinetic SZ effect on almost all angular scales.