Gas Clumping in the Outskirts of Lambda-CDM Clusters

TL;DR

This paper investigates how gas clumping affects X-ray measurements of galaxy cluster outskirts, showing it causes overestimated gas density and flattened entropy profiles, which impacts the interpretation of observational data.

Contribution

The study demonstrates through simulations that gas clumping significantly biases X-ray derived ICM profiles in cluster outskirts, highlighting the need to account for clumping in data analysis.

Findings

Gas clumping causes overestimation of gas density.

Clumping leads to flattened entropy profiles.

Results align with Suzaku X-ray observations.

Abstract

Recent Suzaku X-ray observations revealed that the observed entropy profile of the intracluster medium (ICM) deviates significantly from the prediction of hydrodynamical simulations of galaxy clusters. In this work, we show that gas clumping introduces significant biases in X-ray measurements of the ICM profiles in the outskirts of galaxy clusters. Using hydrodynamical simulations of galaxy cluster formation in a concordance Lambda-CDM model, we demonstrate that gas clumping leads to an overestimate of the observed gas density and causes flattening of the entropy profile. Our results suggest that gas clumping must be taken into account when interpreting X-ray measurements of cluster outskirts.