Author ORCID Identifier
Document Type
Article
Publication Date
8-25-2023
Abstract
We probed the dynamical mass profiles of ten galaxy clusters from the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS) using galaxy kinematics. We numerically solved the spherical Jeans equation and parameterize the dynamical mass profile and the galaxy velocity anisotropy profile using two general functions to ensure that our results are not biased toward any specific model. The mass-velocity anisotropy degeneracy is ameliorated by using two virial shape parameters that depend on the fourth moment of velocity distribution. The resulting velocity anisotropy estimates consistently show a nearly isotropic distribution in the inner regions, with an increasing radial anisotropy toward large radii. We compared our derived dynamical masses with those calculated from X-ray gas data assuming hydrostatic equilibrium, finding that massive and rich relaxed clusters generally present consistent mass measurements, while unrelaxed or low-richness clusters have systematically larger total masses than hydrostatic masses by, on average, 50%. This might help alleviate current tensions in the measurement of I8, but it also leads to cluster baryon fractions below the cosmic value. Finally, our approach probes accelerations as low as 10-11 m s-2, comparable to the outskirts of individual late-type galaxies. We confirm that galaxy clusters deviate from the radial acceleration relation defined by galaxies.
Keywords
cosmology: observations, dark matter, galaxies: clusters: general, galaxies: clusters: intracluster medium, X-rays: galaxies: clusters
Publication Title
Astronomy and Astrophysics
Grant
1911909
Rights
© The Authors 2023. This is an Open Access work distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Measuring galaxy cluster mass profiles into the low-acceleration regime with galaxy kinematics Pengfei Li, Yong Tian, Mariana P. Júlio, Marcel S. Pawlowski, Federico Lelli, Stacy S. McGaugh, James M. Schombert, Justin I. Read, Po-Chieh Yu and Chung-Ming Ko A&A, 677 (2023) A24 DOI: https://doi.org/10.1051/0004-6361/202346431
Manuscript Version
Final Publisher Version