Issue |
A&A
Volume 687, July 2024
|
|
---|---|---|
Article Number | A58 | |
Number of page(s) | 14 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/202348701 | |
Published online | 27 June 2024 |
CHEX-MATE: Turbulence in the intra-cluster medium from X-ray surface brightness fluctuations
1
IRAP, Université de Toulouse, CNRS, CNES, UT3-PS, Toulouse, France
e-mail: sdupourque@irap.omp.eu
2
Department of Astronomy, University of Geneva, Ch. d’Ecogia 16, 1290 Versoix, Switzerland
3
Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544-1001, USA
4
Dipartimento di Fisica e Astronomia, Universitá di Bologna, Via Gobetti 93/2, 40122 Bologna, Italy
5
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
6
Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
7
INAF, Osservatorio di Trieste, v. Tiepolo 11, 34131 Trieste, Italy
8
IFPU, Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
9
Istituto Nazionale di Astrofisica, IASF-Milano, Via A. Corti 12, 20133 Milano, Italy
10
Hamburger Sternwarte, University of Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
11
Istituto di Radioastronomia, INAF, Via Gobetti 101, 40122 Bologna, Italy
12
INAF, Osservatorio di Astrofisica e Scienza dello Spazio, Via Piero Gobetti 93/3, 40129 Bologna, Italy
13
DiSAT, Università degli Studi dell’Insubria, Via Valleggio 11, 22100 Como, Italy
14
Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
15
Università degli studi di Roma “Tor Vergata”, Via della ricerca scientifica, 1, 00133 Roma, Italy
16
INFN, Sezione di Roma 2, Università degli studi di Roma Tor Vergata, Via della Ricerca Scientifica, 1, Roma, Italy
Received:
22
November
2023
Accepted:
4
March
2024
The intra-cluster medium is prone to turbulent motion that will contribute to the non-thermal heating of the gas, complicating the use of galaxy clusters as cosmological probes. Indirect approaches can estimate the intensity and structure of turbulent motions by studying the associated fluctuations in gas density and X-ray surface brightness. In this work, we aim to constrain the gas density fluctuations occurring in the CHEX-MATE sample to obtain a detailed view of their properties in a large population of clusters. To do so, we use a simulation-based approach to constrain the parameters of the power spectrum of density fluctuations, assuming a Kolmogorov-like spectrum and including the stochastic nature of the fluctuation-related observables in the error budget. Using a machine-learning approach, we learn an approximate likelihood for each cluster. This method requires clusters not to be too disturbed, as fluctuations can originate from dynamic processes such as merging. Accordingly, we removed the less relaxed clusters (centroid shift w > 0.02) from our sample, resulting in a sample of 64 clusters. We defined different subsets of CHEX-MATE to determine properties of density fluctuations as a function of dynamical state, mass, and redshift, and we investigated the correlation with the presence or not of a radio halo. We found a positive correlation between the dynamical state and density fluctuation variance, a non-trivial behaviour with mass, and no specific trend with redshift or the presence of a radio halo. The injection scale is mostly constrained by the core region. The slope in the inertial range is consistent with the Kolmogorov theory. When interpreted as originating from turbulent motion, the density fluctuations in R500 yield an average Mach number of ℳ3D ≃ 0.4 ± 0.2, an associated non-thermal pressure support of Pturb/Ptot ≃ (9 ± 6)%, or a hydrostatic mass bias bturb ≃ 0.09 ± 0.06. These findings align with expectations from existing literature.
Key words: turbulence / galaxies: clusters: intracluster medium / X-rays: galaxies: clusters
© 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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