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

摘要

Turbulent gas motion inside galaxy clusters provides a non-negligiblenon-thermal pressure support to the intracluster gas. If not corrected, itleads to a systematic bias in the estimation of cluster masses from X-ray andSunyaev-Zel'dovich (SZ) observations assuming hydrostatic equilibrium, andaffects interpretation of measurements of the SZ power spectrum andobservations of cluster outskirts from ongoing and upcoming large clustersurveys. Recently, Shi & Komatsu developed an analytical model for predictingthe radius, mass, and redshift dependence of the non-thermal pressurecontributed by the kinetic random motions of intracluster gas sourced by thecluster mass growth. In this paper, we compare the predictions of thisanalytical model to a state-of-the-art cosmological hydrodynamics simulation.As different mass growth histories result in different non-thermal pressure, weperform the comparison on 65 simulated galaxy clusters on a cluster-by-clusterbasis. We find an excellent agreement between the modelled and simulatednon-thermal pressure profiles. Our results open up the possibility of using theanalytical model to correct the systematic bias in the mass estimation ofgalaxy clusters. We also discuss tests of the physical picture underlying theevolution of intracluster non-thermal gas motions, as well as a way to furtherimprove the analytical modeling, which may help achieve a unified understandingof non-thermal phenomena in galaxy clusters.