The Baryonic Mass-Halo Mass Relation of Extragalactic Systems
Abstract
We combine data for extragalactic systems to quantify a relation between the observed baryonic mass and the enclosed dynamical mass inferred from kinematics or gravitational lensing. Our sample covers nine orders of magnitude in baryonic mass, including galaxies with kinematic or weak gravitational lensing data and groups and clusters of galaxies with new gravitational lensing data. For rich clusters with , the observed baryon fraction is consistent with the cosmic value, . For lower masses, the baryon fraction decreases systematically with mass. The variation is well described by with . This relation is qualitatively similar to stellar mass-halo mass relations derived from abundance matching, but exhibits less scatter.
Cite
@article{arxiv.2603.06479,
title = {The Baryonic Mass-Halo Mass Relation of Extragalactic Systems},
author = {Stacy McGaugh and Tobias Mistele and Francis Duey and Konstantin Haubner and Federico Lelli and Jim Schombert and Pengfei Li},
journal= {arXiv preprint arXiv:2603.06479},
year = {2026}
}
Comments
Accepted for publication in the Astrophysical Journal. 36 pages, 9 figures