Comment on the Noerdlinger hypothesis

Diffuse X-radiation resulting from intergalactic gas in clusters of galaxies is computed, on the assumption that all galaxies originally formed as members of compact clusters which contained enough gas to bind them gravitationally. This hypothesis is shown to be untenable if thermal energy is transferred to the gas in order to expand or dissolve the clusters. Subject headings: cosmology - galaxies, clusters of - intergalactic medium - X-rays