A test of the evolution of gas depletion factor in galaxy clusters using strong gravitational lensing systems

TL;DR

This study investigates how the gas depletion factor in galaxy clusters evolves with redshift using strong gravitational lensing and X-ray data, finding a mild decrease over time, challenging previous assumptions of constancy.

Contribution

It introduces a novel method combining X-ray and lensing data to test the redshift evolution of the gas depletion factor in galaxy clusters.

Findings

Gas depletion factor mildly decreases with redshift

First evidence against a constant depletion factor in literature

Uses 40 measurements from multiple lensing surveys

Abstract

In this letter, we discuss a new method to probe the redshift evolution of the gas depletion factor, i.e. the ratio by which the gas mass fraction of galaxy clusters is depleted with respect to the universal mean of baryon fraction. The dataset we use for this purpose consists of 40 gas mass fraction measurements measured at $r_{2500}$ using Chandra X-ray observations, strong gravitational lensing sub-samples obtained from SLOAN Lens ACS + BOSS Emission-line Lens Survey (BELLS) + Strong Legacy Survey SL2S + SLACS. For our analysis, the validity of cosmic distance duality relation is assumed. We find a mildly decreasing trend for the gas depletion factor as a function of redshift at about 2.7$\sigma$. This is the first result in literature which does not find a constant gas depletion factor as a function of redshift using gas mass fraction measurements at $r_{2500}$.