1997/10/30 by Nobuyoshi Makino, Shin Sasaki, Yasushi Suto · 8 citations
Physics and Astronomy · #Astronomy #Astrophysics #Cluster (spacecraft) #Cosmology and Gravitation Theories #Cuspy halo problem #Dark Matter and Cosmic Phenomena #Dark matter #Dark matter halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Halo #Hydrostatic equilibrium #Luminosity #Physics #RADIUS #astro-ph
paper · pdf · doi:10.1086/305507
published as ApJ 497(1998)555 · 11 pages, LaTeX, 4 figures. The Astrophysical Journal Part 1, in press
arxiv created 1997/10/30 · openalex publication_date 1998/04/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The X-ray cluster gas density distribution in hydrostatic equilibrium is computed from the universal density profile of the dark matter halo proposed by Navarro, Frenk, & White in two recent studies. If one assumes the isothermality, the resulting distribution is well approximated by the conventional β-model. We predict the core radius r c , the β-parameter, and the X-ray luminosity of clusters as a function of the temperature T X of clusters in some representative cosmological models and compare them with observations and results of numerical simulations. The predicted size of r c is a factor of 3-10 smaller than the average of observed values. If both the universal density profile and the hydrostatic equilibrium are reasonable approximation to the truth, then this suggests either that the previous X-ray observations systematically overestimated the core radius of gas densities in clusters of galaxies or that some important physical mechanisms, which significantly increase the core radius, are still missing.