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

Rogério Monteiro-Oliveira

Submitted on 5 July 2022


We present the weak lensing mass distribution of a triple merging cluster candidate at zphoto0.36 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 1.70.7+0.5. According to our two-body kinematic description, the encounter happened 0.580.20+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 c200. At the observed merger stage, where the clusters have travelled 55 per cent of the path to reach the apoapsis, the choice of the c200 (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.


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

Subject: Astrophysics - Cosmology and Nongalactic Astrophysics