The concentration-mass relation of clusters of galaxies from the OmegaWINGS survey

TL;DR

This study derives the galaxy cluster concentration-mass relation using dynamical analysis of member galaxies, providing results consistent with theoretical models and recent lensing observations, and highlighting differences from previous measurements.

Contribution

It presents a novel dynamical analysis of the cMr for galaxy clusters using the MAMPOSSt technique on OmegaWINGS data, offering an independent assessment.

Findings

The cMr is in agreement with LambdaCDM simulations.

The derived cMr has a flatter slope and lower normalization than previous observational studies.

Results are consistent with recent lensing-based cMr measurements.

Abstract

The relation between a cosmological halo concentration and its mass (cMr) is a powerful tool to constrain cosmological models of halo formation and evolution. On the scale of galaxy clusters the cMr has so far been determined mostly with X-ray and gravitational lensing data. The use of independent techniques is helpful in assessing possible systematics. Here we provide one of the few determinations of the cMr by the dynamical analysis of the projected-phase-space distribution of cluster members. Based on the WINGS and OmegaWINGS data sets, we used the Jeans analysis with the MAMPOSSt technique to determine masses and concentrations for 49 nearby clusters, each of which has ~60 spectroscopic members or more within the virial region, after removal of substructures. Our cMr is in statistical agreement with theoretical predictions based on LambdaCDM cosmological simulations. Our cMr is different from most previous observational determinations because of its flatter slope and lower normalization. It is however in agreement with two recent cMr obtained using the lensing technique on the CLASH and LoCuSS cluster data sets. In the future we will extend our analysis to galaxy systems of lower mass and at higher redshifts.