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arXiv · 2507.05404

The intracluster light as an estimator of the cluster mass profile

Isaac Alonso Asensio·Ana Contreras-Santos
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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.

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Isaac Alonso Asensio, Ana Contreras-Santos. 2025-08-25. The intracluster light as an estimator of the cluster mass profile. https://doi.org/10.1051/0004-6361%2F202555083

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