Issue |
A&A
Volume 686, June 2024
|
|
---|---|---|
Article Number | A86 | |
Number of page(s) | 19 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/202348583 | |
Published online | 31 May 2024 |
The hot circumgalactic media of massive cluster satellites in the TNG-Cluster simulation: Existence and detectability
1
Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
e-mail: rohr@mpia.de
2
Zentrum für Astronomie der Universität Heidelberg, ITA, Albert Ueberle Str. 2, 69120 Heidelberg, Germany
3
Centre for Astrophysics and Planetary Science, Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
Received:
13
November
2023
Accepted:
27
February
2024
The most massive galaxy clusters in the Universe host tens to hundreds of massive satellite galaxies M⋆ ∼ 1010 − 12.5 M⊙, but it is unclear if these satellites are able to retain their own gaseous atmospheres. We analyze the evolution of ≈90 000 satellites of stellar mass ∼109 − 12.5 M⊙ around 352 galaxy clusters of mass M200c ∼ 1014.3 − 15.4 M⊙ at z = 0 from the new TNG-Cluster suite of cosmological magneto-hydrodynamical galaxy cluster simulations. The number of massive satellites per host increases with host mass, and the mass–richness relation broadly agrees with observations. A halo of mass M200chost ∼ 1014.5(1015) M⊙ hosts ∼100 (300) satellites today. Only a minority of satellites retain some gas, hot or cold, and this fraction increases with stellar mass. lower-mass satellites ∼109 − 10 M⊙ are more likely to retain part of their cold interstellar medium, consistent with ram pressure preferentially removing hot extended gas first. At higher stellar masses ∼1010.5 − 12.5 M⊙, the fraction of gas-rich satellites increases to unity, and nearly all satellites retain a sizeable portion of their hot, spatially extended circumgalactic medium (CGM), despite the ejective activity of their supermassive black holes. According to TNG-Cluster, the CGM of these gaseous satellites can be seen in soft X-ray emission (0.5−2.0 keV) that is, ≳10 times brighter than the local background. This X-ray surface brightness excess around satellites extends to ≈30 − 100 kpc, and is strongest for galaxies with higher stellar masses and larger host-centric distances. Approximately 10% of the soft X-ray emission in cluster outskirts ≈0.75 − 1.5 R200c originates from satellites. The CGM of member galaxies reflects the dynamics of cluster-satellite interactions and contributes to the observationally inferred properties of the intracluster medium.
Key words: methods: numerical / galaxies: clusters: general / galaxies: clusters: intracluster medium / galaxies: evolution / galaxies: formation / galaxies: halos
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Open access funding provided by Max Planck Society.
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