Primordial inhomogeneities in the expanding universe. III - The density velocity distributions in cluster halos as a cosmological probe

Abstract

view Abstract Citations (23) References (13) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Primordial inhomogeneities in the expanding universe. III. The density and velocity distributions in cluster halos as a cosmological probe. Silk, J. ; Wilson, M. L. Abstract A model for the formation of a rich cluster of galaxies is developed that consists of a large number of initially infalling spherical shells of matter. The effects of shell crossings are included, and the density profile and velocity distribution in the cluster halo are computed. The velocity distribution is evaluated for a magnitude-limited sample of galaxies within a 30 radius of the Coma cluster center, and compared with the sample, complete to m = 15.7, of Tifft and Gregory. Models with = 0.1 are found to be acceptable, whereas models with = 0.02 and = 1.1 can tentatively be rejected. However, because of poor statistics, a definitive result requires a deeper sample, to approximately 17th magnitude. The projected density distribution in our models of the Coma cluster halo is evaluated and compared with data by Chincarini and Rood. For 0.1, we find that the outermost halos are appreciably flatter in density profile than would be inferred from the standard equilibrium cluster models. The extent and mass of the cluster halo and the radius within which shell crossings occur are derived. We suggest that this shell crossing radius delineates the maximum probable extent of the hot intracluster gas. Subject headings: cosmology - galaxies: clusters of - galaxies: structure Publication: The Astrophysical Journal Pub Date: November 1979 DOI: 10.1086/157438 Bibcode: 1979ApJ...233..769S Keywords: Astronomical Models; Cosmology; Galactic Clusters; Galactic Structure; Density Distribution; Inhomogeneity; Spherical Shells; Velocity Distribution; Astrophysics; Clusters of Galaxies:Formation; Clusters of Galaxies:Models; Clusters of Galaxies:Structure full text sources ADS |