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Correlations in the matter distribution in CLASH galaxy clusters

A. Del Popolo, M. Le Delliou, X. Lee

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 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 α=0.30 to 0.79. We examine correlations of the DM density slope α with the effective radius Re and stellar mass Me of the BCG, finding that these quantities are anti-correlated with a Spearman correlation coefficient of ∼ -0.6 . We also study the correlation between Re and the cluster halo mass M500, 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.

Keywords
Galaxy clusters; Galaxy formation; Weak gravitational lensing; Astrophysics - Cosmology and Nongalactic Astrophysics

Physics of the Dark Universe
Volume 26
2019 December

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia