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arXiv · 2509.07777

A comprehensive separation of dark matter and baryonic mass components in galaxy clusters II: an overview of the mass distribution in Abell S1063

Benjamin Beauchesne·Benjamin Clément·Marceau Limousin·Anna Niemiec·Mathilde Jauzac·Belén Alcalde Pampliega·Johan Richard·Guillaume Mahler·Jose M. Diego·Pascale Hibon·Anton M. Koekemoer·Thomas Connor·Jean-Paul Kneib·Andreas L. Faisst
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Abstract

In the first paper of this series, we derived mass constraints on the total mass and the baryonic components of the galaxy cluster Abell S1063. The main focus was to recover stellar masses and kinematics for cluster members, the brightest cluster galaxy (BCG) and the intra-cluster light (ICL). In this second paper, we introduce a multi-probe mass modelling approach that incorporates constraints on both the total mass and the individual baryonic components. We obtain comprehensive mass models of Abell S1063, in which the dark matter distribution is disentangled from the baryonic mass at both cluster and galaxy scales. The best-fitting mass model achieves an RMS of $0.50"$ on the multiple image positions. The kinematic profiles of the BCG \& ICL, as well as the X-ray surface brightness of the intra-cluster gas, are accurately reproduced within observational uncertainties. However, a $35~\mathrm{km/s}$ scatter is required for the cluster member line-of-sight dispersions. This method yields the most complex parametric mass model with consistency among almost all available mass constraints. We find a $1σ$ agreement between the inferred stellar-to-subhalo mass relation and that predicted by large-scale cosmological simulations. The ICL stellar mass derived from our model is consistent with estimates from stellar population modelling. We present the first multi-probe mass modelling method capable of disentangling the dark matter from the baryonic mass distributions in massive galaxy clusters. Its results, such as the stellar-to-subhalo mass relation or the distribution of each mass component, can be directly compared to hydrodynamical cosmological simulations such as illustrisTNG.

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Benjamin Beauchesne, Benjamin Clément, Marceau Limousin, Anna Niemiec, Mathilde Jauzac, Belén Alcalde Pampliega, Johan Richard, Guillaume Mahler, Jose M. Diego, Pascale Hibon, Anton M. Koekemoer, Thomas Connor, Jean-Paul Kneib, Andreas L. Faisst. 2026-07-24. A comprehensive separation of dark matter and baryonic mass components in galaxy clusters II: an overview of the mass distribution in Abell S1063. https://doi.org/10.1093/mnras%2Fstag829

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