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arXiv · 2305.02353

Witnessing the intracluster medium assembly at the cosmic noon in JKCS041

S. Andreon·C. Romero·H. Aussel·T. Bhandarkar·M. Devlin·S. Dicker·B. Ladjelate·I. Lowe·B. Mason·T. Mroczkowski·A. Raichoor·C. Sarazin·G. Trinchieri
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Abstract

In this work we study the intracluster medium of a galaxy cluster at the cosmic noon: JKCS041 at z=1.803. A 28h long Sunyaev-Zel'dovich (SZ) observation using MUSTANG-2 allows us to detect JKCS041, even if intrinsically extremely faint compared to other SZ-detected clusters. We found that the SZ peak is offset from the X-ray center by about 220 kpc in the direction of the brightest cluster galaxy, which we interpret as due to the cluster being observed just after first passage of a major merger. JKCS041 has a low central pressure and a low Compton Y compared to local clusters selected by their intracluster medium (ICM), likely because the cluster is still in the process of assembly but also in part because of a hard-to-quantify bias in current local ICM-selected samples. JKCS041 has a 0.5 dex fainter Y signal than another less massive z~1.8 cluster, exemplifying how much different weak-lensing mass and SZ mass can be at high redshift. The observations we present provide us with the measurement of the most distant resolved pressure profile of a galaxy cluster. Comparison with a library of plausibly descendants shows that JKCS041 pressure profile will likely increase by about 0.7 dex in the next 10 Gyr at all radii.

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S. Andreon, C. Romero, H. Aussel, T. Bhandarkar, M. Devlin, S. Dicker, B. Ladjelate, I. Lowe, B. Mason, T. Mroczkowski, A. Raichoor, C. Sarazin, G. Trinchieri. 2023-05-03. Witnessing the intracluster medium assembly at the cosmic noon in JKCS041. https://doi.org/10.1093/mnras%2Fstad1270

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