Are the virial masses of clusters smaller than we think?

Citations Over TimeTop 10% of 1987 papers

Abstract

The constraints that the available X-ray spectral and imaging data place on the mass distribution and mass to light ratio of rich clusters are considered. It was found for the best determined cases that the mass to light ratio is less than 125 h₅₀ at radii exceeding 1 h₅₀ Mpc. The mass to light ratio is approximately constant at radii exceeding 1 h₅₀ Mpc but may rise to values of roughly 200 h₅₀ in the central regions. The fraction of the total mass that is in baryons, primarily the hot X-ray emitting gas, is roughly 30 percent thus setting the mass to light ratio of the dark material to roughly 70. The model that fits the X-ray data for Coma is in good agreement with the observed optical velocity dispersion vs. radius data.

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