The Impact of Cooling and Preheating on the Sunyaev-Zeldovich Effect

Abstract

We use hydrodynamical simulations to assess the impact of radiative cooling and "preheating" on predictions for the Sunyaev-Zeldovich (SZ) effect. Cooling significantly reduces both the mean SZ signal and its angular power spectrum, while preheating can increase the mean distortion while leaving the angular power spectrum below that found in a simulation without heating or cooling. We study the relative contribution from high- and low-density gas, and we find that in the cooling model about 60% of the mean thermal distortion arises from low-overdensity gas. We find that halos dominate the thermal SZ power spectrum in all models, while in the cooling simulation the kinetic SZ power spectrum originates predominantly in lower overdensity gas.