Cosmic‐Ray Protons and Magnetic Fields in Clusters of Galaxies and Their Cosmological Consequences

The masses of clusters of galaxies estimated by gravitational lensing exceedin many cases the mass estimates based on hydrostatic equilibrium. This maysuggest the existence of nonthermal pressure. We ask if radio galaxies can heatand support the cluster gas with injected cosmic ray protons and magnetic fielddensities, which are permitted by Faraday rotation and gamma ray observationsof clusters of galaxies. We conclude that they are powerful enough to do thiswithin a cluster radius of roughly 1 Mpc. If present, nonthermal pressurescould lead to a revised estimate of the ratio of baryonic mass to total mass,and the apparent baryonic overdensity in clusters would disappear. Inconsequence, $\Omega_{\rm cold}$, the clumping part of the cosmological density$\Omega_{o}$, would be larger than $0.4\,h_{50}^{-1/2}$.Comment: Accepted by ApJ, 16 pages, LaTeX, 2 figures, epsfig.sty, aaspp4.st