Analytical model for non-thermal pressure in galaxy clusters - II.
  Comparison with cosmological hydrodynamics simulation
  Turbulent gas motion inside galaxy clusters provides a non-negligible
non-thermal pressure support to the intracluster gas. If not corrected, it
leads to a systematic bias in the estimation of cluster masses from X-ray and
Sunyaev-Zel'dovich (SZ) observations 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 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 this paper, we compare the predictions of this
analytical model to a state-of-the-art cosmological 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 modelled 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 physical picture underlying the
evolution of intracluster non-thermal gas motions, as well as a way to further
improve the analytical modeling, which may help achieve a unified understanding
of non-thermal phenomena in galaxy clusters.
