Detection of anti-correlation of hot and cold baryons in galaxy clusters

Arya Farahi; Sarah L Mulroy; August E Evrard; Graham P Smith; Alexis Finoguenov; Hervé Bourdin; John E Carlstrom; Chris P Haines; Daniel P Marrone; Rossella Martino; Pasquale Mazzotta; Christine O'Donnell; Nobuhiro Okabe

doi:10.1038/s41467-019-10471-y

Detection of anti-correlation of hot and cold baryons in galaxy clusters

Nat Commun. 2019 Jul 2;10(1):2504. doi: 10.1038/s41467-019-10471-y.

Authors

Arya Farahi^{1

2}, Sarah L Mulroy³, August E Evrard^{4

5}, Graham P Smith³, Alexis Finoguenov^{6

7}, Hervé Bourdin^{8

9}, John E Carlstrom¹⁰, Chris P Haines¹¹, Daniel P Marrone¹², Rossella Martino⁹, Pasquale Mazzotta^{8

9}, Christine O'Donnell¹², Nobuhiro Okabe^{13

14

15}

Affiliations

¹ Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA. aryaf@umich.edu.
² McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, Pittsburgh, PA, 15213, USA. aryaf@umich.edu.
³ School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, England.
⁴ Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
⁵ Department of Astronomy, University of Michigan, Ann Arbor, MI, 48109, USA.
⁶ Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, 00014, Helsinki, Finland.
⁷ Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse, 85741, Garching, Germany.
⁸ Harvard Smithsonian Centre for Astrophysics, 60 Garden Street, Cambridge, MA, 02138, USA.
⁹ Dipartimento di Fisica, Università degli Studi di Roma "Tor Vergata", via della Ricerca Scientifica 1, 00133, Roma, Italy.
¹⁰ Kavli Institute for Cosmological Physics, Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, 60637, USA.
¹¹ INAF - Osservatorio Astronomico di Brera, Via Brera 28, 20122, Milano, Italy.
¹² Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ, 85721, USA.
¹³ Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.
¹⁴ Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.
¹⁵ Core Research for Energetic Universe, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.

Abstract

The largest clusters of galaxies in the Universe contain vast amounts of dark matter, plus baryonic matter in two principal phases, a majority hot gas component and a minority cold stellar phase comprising stars, compact objects, and low-temperature gas. Hydrodynamic simulations indicate that the highest-mass systems retain the cosmic fraction of baryons, a natural consequence of which is anti-correlation between the masses of hot gas and stars within dark matter halos of fixed total mass. We report observational detection of this anti-correlation based on 4 elements of a 9 × 9-element covariance matrix for nine cluster properties, measured from multi-wavelength observations of 41 clusters from the Local Cluster Substructure Survey. These clusters were selected using explicit and quantitative selection rules that were then encoded in our hierarchical Bayesian model. Our detection of anti-correlation is consistent with predictions from contemporary hydrodynamic cosmological simulations that were not tuned to reproduce this signal.