Analytical model for non-thermal pressure in galaxy clusters – II. Comparison with cosmological hydrodynamics simulation

Abstract

Turbulent gas motion inside galaxy clusters provides a non-negligible non-thermal pressure support to the intracluster gas. If not corrected, it leads t o a systematic bias in the estimation of cluster masses from X-ray and Sunyaev-Zel’dovich (SZ) obse rvations assuming hydrostatic equilibrium, and affects interpretation of measurements of the SZ power spectrum and observations of cluster outskirts from ongoing and upcoming large cluster surveys. Recently, Shi & Komatsu (2014) developed an analytical model for predicting the radius, mass, and redshift dependence of the non-thermal pressure contributed by the kinetic random motions of intracluster gas sourced by the cluster mass growth. In th is paper, we compare the predictions of this analytical model to a state-of-the-art cosmol ogical hydrodynamics simulation. As different mass growth histories result in different non- thermal pressure, we perform the comparison on 65 simulated galaxy clusters on a cluster-by-cluster basis. We find an excellent agreement between the modeled and simulated non-thermal pressure profiles. Our results open up the possibility of using the analytical model to correct the systematic bias in the mass estimation of galaxy clusters. We also discuss tests of the p hysical picture underlying the evolution of intracluster turbulence, as well as a way to fur ther improve the analytical modeling, which may help achieve a unified understanding of non- thermal phenomena in galaxy clusters.