Issue |
A&A
Volume 663, July 2022
|
|
---|---|---|
Article Number | L6 | |
Number of page(s) | 8 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202244068 | |
Published online | 21 July 2022 |
Letter to the Editor
Mapping ‘out-of-the-box’ the properties of the baryons in massive halos
1
Dipartimento di Fisica e Astronomia, Universitá di Bologna, Via Gobetti 92/3, 40121 Bologna, Italy
e-mail: matteo.angelinelli2@unibo.it
2
INAF, Osservatorio di Astrofisica e Scienza dello Spazio, Via Pietro Gobetti 93/3, 40121 Bologna, Italy
3
INFN, Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy
4
Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.1, 81679 München, Germany
5
Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85741 Garching, Germany
6
Hamburger Sternwarte, University of Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
7
Istituto di Radio Astronomia, INAF, Via Gobetti 101, 40121 Bologna, Italy
8
INAF, Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, 34143 Trieste, Italy
9
IFPU, Institute for Fundamental Physics of the Universe, Via Beirut 2, 34014 Trieste, Italy
Received:
20
May
2022
Accepted:
23
June
2022
We study the distributions of the baryons in massive halos (Mvir > 1013 h−1 M⊙) in the Magneticum suite of smoothed particle hydrodynamical cosmological simulations, out to the unprecedented radial extent of 10R500, c. We confirm that, under the action of non-gravitational physical phenomena, the baryon mass fraction is lower in the inner regions (< R500, c) of increasingly less massive halos, and rises moving outwards, with values that span from 51% (87%) of the cosmological value in the regions around R500, c to 95% (100%) at 10R500, c in the systems with the lowest (highest; Mvir ∼ 5 × 1014 h−1 M⊙) masses. The galaxy groups almost match the gas (and baryon) fraction measured in the most massive halos only at very large radii (r > 6R500, c), where the baryon depletion factor Ybar = fbar/(Ωb/Ωm) approaches the value of unity, expected for ‘closed-box’ systems. We find that both the radial and mass dependence of the baryon, gas, and hot depletion factors are predictable and follow a simple functional form. The star mass fraction is higher in less massive systems, decreases systematically with increasing radii, and reaches a constant value of Ystar ≈ 0.09, where the gas metallicity is also constant, regardless of the host halo mass, as a result of the early (z > 2) enrichment process.
Key words: methods: numerical / large-scale structure of Universe / galaxies: clusters: intracluster medium / galaxies: groups: general / hydrodynamics / galaxies: clusters: general
© M. Angelinelli et al. 2022
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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