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A study of galaxy groups and clusters - The case for a clumpy intergalactic medium.A nonuniform model for a dense intergalactic medium is constructed under the assumption that all groups and clusters of galaxies are gravitationally bound by ionized gas. Catalogs by de Vaucouleurs and Abell are utilized to provide an almost complete sample of the spatial distribution of groups and clusters over a wide range of richness, and a distribution function is derived for galaxy groups and clusters as a function of velocity dispersion. A simple scaling law is applied to predict velocity dispersions for the very rich Abell clusters. Thermal bremsstrahlung emission from the intracluster gas accounts for the observed emission over 2 to 10 keV from several rich clusters, and also contributes up to 20% of the diffuse X-ray background over a considerable fraction of the observed range. The amount of X-ray emitting gas is restricted to a small fraction of the virial mass, with the remainder of the binding mass present as cooler ionized clouds. Available soft X-ray and ultraviolet diffuse background observations are used to define a narrow range of permissible temperatures and densities for these clouds.
Document ID
19730052806
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Silk, J.
Tarter, J.
(California, University Berkeley, Calif., United States)
Date Acquired
August 7, 2013
Publication Date
July 15, 1973
Publication Information
Publication: Astrophysical Journal
Volume: 183
Subject Category
Space Sciences
Accession Number
73A37608
Funding Number(s)
CONTRACT_GRANT: NGR-05-003-453
Distribution Limits
Public
Copyright
Other

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