Correlations in the matter distribution in CLASH galaxy clusters

TL;DR

This study analyzes the dark matter and total matter density profiles in 15 high-mass galaxy clusters, revealing how baryonic physics influence the inner dark matter distribution and identifying key correlations among cluster properties.

Contribution

It extends previous work by analyzing a larger sample of CLASH clusters, demonstrating the impact of baryonic physics on dark matter profiles and establishing correlations among cluster characteristics.

Findings

Inner dark matter slopes are flatter than NFW profiles, ranging from 0.30 to 0.79.

Anti-correlation between DM slope and BCG effective radius and stellar mass.

Positive correlation between BCG effective radius, halo mass, and total mass within 5 and 100 kpc.

Abstract

We study the total and dark matter (DM) density profiles as well as their correlations for a sample of 15 high-mass galaxy clusters by extending our previous work on several clusters from Newman et al. Our analysis focuses on 15 CLASH X-ray-selected clusters that have high-quality weak- and strong-lensing measurements from combined Subaru and {\em Hubble Space Telescope} observations. The total density profiles derived from lensing are interpreted based on the two-phase scenario of cluster formation. In this context, the brightest cluster galaxy (BCG) forms in the first dissipative phase, followed by a dissipationless phase where baryonic physics flattens the inner DM distribution. This results in the formation of clusters with modified DM distribution and several correlations between characteristic quantities of the clusters. We find that the central DM density profiles of the clusters are strongly influenced by baryonic physics as found in our earlier work. The inner slope of the DM density for the CLASH clusters is found to be flatter than the Navarro--Frenk--White profile, ranging from $\alpha=0.30$ to $0.79$. We examine correlations of the DM density slope $\alpha$ with the effective radius $R_\mathrm{e}$ and stellar mass $M_\mathrm{e}$ of the BCG, finding that these quantities are anti-correlated with a Spearman correlation coefficient of $\sim -0.6$. We also study the correlation between $R_\mathrm{e}$ and the cluster halo mass $M_{500}$, and the correlation between the total masses inside 5\,kpc and 100\,kpc. We find that these quantities are correlated with Spearman coefficients of $0.68$ and $0.64$, respectively. These observed correlations are in support of the physical picture proposed by Newman et al.