PREPRINT
E4738717-2B11-43AE-9984-CD7D5BD3142C

# A major galaxy cluster merger caught by eROSITA: weak lensing mass distribution and kinematic description

Rogério Monteiro-Oliveira
arXiv:2207.02232

Submitted on 5 July 2022

## Abstract

We present the weak lensing mass distribution of a triple merging cluster candidate at ${z}_{\mathrm{p}\mathrm{h}\mathrm{o}\mathrm{t}\mathrm{o}}\sim 0.36$ belonging to a supercluster recently discovered during the eROSITA Performance Verification phase. Our analysis solved a previous tension in the merger classification by confirming that the cluster pair eFEDS J093513.3+004746 and eFEDS J093510.7+004910 is undergoing a major merger with a mass ratio ${1.7}_{-0.7}^{+0.5}$. According to our two-body kinematic description, the encounter happened ${0.58}_{-0.20}^{+0.15}$ Gyr ago, in a scenario that supports the observed radio relic position at the cluster outskirts. However, the same analysis showed that the companion cluster, eFEDS J093501.1+005418, is not gravitationally bound to the interacting system and therefore it is not part of the supercluster. We also checked the impact of adopting a scaling relation to determine the halo concentration ${c}_{200}$. At the observed merger stage, where the clusters have travelled $\sim$55 per cent of the path to reach the apoapsis, the choice of the ${c}_{200}$ (whether from a scaling relation or a free parameter in the mass model) does not change significantly either the cluster masses or the kinematic description.

## Preprint

Comment: 12 pages, 9 figures, 4 tables. Submitted to MNRAS (2nd revision)

Subject: Astrophysics - Cosmology and Nongalactic Astrophysics