CHEX-MATE: towards a consistent universal pressure profile and cluster mass reconstruction

TL;DR

This paper introduces a novel joint fitting method to accurately determine universal pressure profiles and individual cluster masses, improving mass estimates and reducing biases in galaxy cluster studies.

Contribution

It presents the first joint fitting approach for universal pressure profiles and cluster masses, accounting for correlations and scaling, enhancing mass estimation accuracy.

Findings

The method yields cluster masses with accuracy and precision surpassing input estimates.

Application to a sample of 25 clusters demonstrates the method's effectiveness.

Proper modeling of pressure profiles avoids biases in cluster mass reconstruction.

Abstract

In a self-similar paradigm of structure formation, the thermal pressure of the hot intra-cluster gas follows a universal distribution once the profile of each cluster is normalised based on the proper mass and redshift dependencies. The reconstruction of such a universal pressure profile requires an individual estimate of the mass of each cluster. In this context, we present a method to jointly fit, for the first time, the universal pressure profile and individual cluster $M_{500}$ masses over a sample of galaxy clusters, properly accounting for correlations between the profile shape and amplitude, and masses scaling the individual profiles. We demonstrate the power of the method and show that a consistent exploitation of the universal pressure profile and cluster mass estimates when modelling the thermal pressure in clusters is necessary to avoid biases. In particular, the method, informed by a cluster mass scale, outputs individual cluster masses with same accuracy and better precision than input masses. Using data from the {\guillemotleft}Cluster HEritage project with XMM-Newton: Mass Assembly and Thermodynamics at the Endpoint of structure formation{\guillemotright}, we investigate a sample of $\sim 25$ galaxy clusters spanning mass and redshift ranges of $2 \lesssim M_{500}/10^{14} \; \mathrm{M}_{\odot} \lesssim 14$ and $0.07 < z < 0.6$.