Sunyaev-Zeldovich effect from hydrodynamical simulations: maps and low order statistics

Abstract

We use moving mesh hydrodynamical simulations to make maps of Sunyaev-Zeldovich effect. We present these maps for several cosmological models and explore their lowest moments. We find that the first moment, the mean Compton $y$ parameter, is typically between $1-2\times 10^{-6}$ for cluster abundance normalized models, the lower value corresponding to the high density models, and scales as $σ_8^{3-4}$. Rms fluctuations at 10&#39; scale have an amplitude $ ΔT/T \sim 1-3 \times 10^{-6}$ in the Rayleigh-Jeans regime. The amplitude of the power spectrum strongly depends on the power spectrum normalization and scales as $σ_8^{6-9}$. On smaller scales ($l>1000$) the spectrum is dominated by halos below $10^{13}M_{\sun}$ and so is sensitive to the thermal history of galactic halo gas. On larger scales ($l<1000$) the power spectrum is less sensitive to nongravitational energy injection, but becomes very noisy, with large field to field variations in the power spectrum caused by rare bright sources in the maps, which dominate in the spectrum over the large scale structure correlations. Cross-correlation power spectrum with weak lensing or projected galaxy distribution is significant and the cross-correlation coefficient is around 0.5 over a wide range of scales. Comparison with Press-Schechter predictions gives very good agreement for all the statistics, indicating that there is no significant contribution to SZ from non-virialized structures. The one point distribution function shows clear deviations from gaussianity and can be well-approximated as log-normal on small scales.