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arXiv · 2307.06804

CLASH-VLT: The inner slope of the MACS J1206.2-0847 dark matter density profile

A. Biviano·L. Pizzuti·A. Mercurio·B. Sartoris·P. Rosati·S. Ettori·M. Girardi·C. Grillo·G. B. Caminha·M. Nonino
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Abstract

The inner slope (gammadm) of the dark matter (DM) density profile of cosmological halos carries information about the properties of DM and/or baryonic processes affecting the halo gravitational potential. Cold DM cosmological simulations predict steep inner slopes, gammadm~1. We test this prediction on the MACS J1206.2-0847 cluster at redshift z=0.44, whose DM density profile was claimed to be cored at the center. We determine the cluster DM density profile from 2 kpc from the cluster center to the virial radius (~2 Mpc), using the velocity distribution of ~500 cluster galaxies and the internal velocity dispersion profile of the Brightest Cluster Galaxy (BCG), obtained from VIMOS@VLT and MUSE@VLT data. We solve the Jeans equation of dynamical equilibrium using an upgraded version of the MAMPOSSt method. The total mass profile is modeled as a sum of a generalized-NFW profile that describes the DM component, allowing for a free inner slope of the density profile, a Jaffe profile that describes the BCG stellar mass component, and a non-parametric baryonic profile that describes the sum of the remaining galaxy stellar mass and of the hot intra-cluster gas mass. Our total mass profile is in remarkable agreement with independent determinations based on X-ray observations and strong lensing. We find gammadm=0.7 (-0.1 +0.2) (68\% confidence levels), consistent with predictions from recent LambdaCDM cosmological numerical simulations.

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A. Biviano, L. Pizzuti, A. Mercurio, B. Sartoris, P. Rosati, S. Ettori, M. Girardi, C. Grillo, G. B. Caminha, M. Nonino. 2023-07-13. CLASH-VLT: The inner slope of the MACS J1206.2-0847 dark matter density profile. https://doi.org/10.3847/1538-4357%2Facf832

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