The intracluster light as an estimator of the cluster mass profile

TL;DR

This paper investigates the potential of using intracluster light as an independent method to estimate galaxy cluster mass profiles, leveraging high-resolution simulations and observational data, with promising results compared to traditional techniques.

Contribution

It introduces a novel, simulation-calibrated model linking intracluster stellar mass to total mass, enabling independent cluster mass estimation from ICL observations.

Findings

The ICL-to-mass ratio follows a power law with fitted parameters.

The method estimates the Perseus cluster mass consistent with velocity dispersion data.

Results are compatible with lensing-based mass estimates for other clusters.

Abstract

Context. The intracluster light (ICL) comprises stars that are not bound to individual galaxies within a galaxy cluster, and it provides insights into the cluster mass distribution, evolutionary history, and dynamical state. Aims. We study the viability of the intracluster stellar mass as a proxy for computing the total mass profiles of galaxy clusters. Methods. High-resolution simulations from the C-EAGLE project were used to study the ratio of the intracluster stellar mass and total matter projected densities. This ratio follows a power law, and we present a model for its fit parameters and associated errors. Results. We used this relation to estimate the mass profile of the Perseus cluster based on Euclid observations that extend up to one-third of the virial radius. The obtained cluster mass is compatible with other measurements from galaxy velocity dispersion, but it is overestimated by a factor of two compared to X-ray mass estimates. We repeated this process for four clusters in the Hubble Frontier Fields, finding compatibility with weak- and strong-lensing mass estimates. Conclusions. This method provides an independent approach to cluster mass estimation that is based solely on the observed ICL and a simulation-calibrated relation.