Analytical model for non-thermal pressure in galaxy clusters - III. Removing the hydrostatic mass bias

TL;DR

This paper presents an analytical correction method for non-thermal pressure in galaxy clusters, effectively removing hydrostatic mass bias across various cluster states and observational methods, improving mass estimates for cosmological studies.

Contribution

The authors extend the Shi & Komatsu 2014 model to accurately correct hydrostatic mass bias caused by non-thermal pressure from gas motions in galaxy clusters.

Findings

The correction reduces mass bias in both relaxed and disturbed clusters.

It is applicable regardless of the mass estimation technique.

The method improves mass estimates from X-ray and SZ observations across redshifts.

Abstract

Non-thermal pressure in galaxy clusters leads to underestimation of the mass of galaxy clusters based on hydrostatic equilibrium with thermal gas pressure. This occurs even for dynamically relaxed clusters that are used for calibrating the mass-observable scaling relations. We show that the analytical model for non-thermal pressure developed in Shi & Komatsu 2014 can correct for this so-called 'hydrostatic mass bias', if most of the non-thermal pressure comes from bulk and turbulent motions of gas in the intracluster medium. Our correction works for the sample average irrespective of the mass estimation method, or the dynamical state of the clusters. This makes it possible to correct for the bias in the hydrostatic mass estimates from X-ray surface brightness and the Sunyaev-Zel'dovich observations that will be available for clusters in a wide range of redshifts and dynamical states.