Key points are not available for this paper at this time.
The mass of the Coma Cluster of galaxies has been determined from X-ray data using a general technique which allows for direct comparison with optical results. The preferred model for both sets of data is one in which the mass distribution follows the distribution of the optical light. The total virial mass within 5h₅0_^-1^ Mpc is (1. 85 + 0. 24) x 10¹5ʰ₅0_^-1^ Mₛun_, and the mass-to-light ratio is 165 +/- 25h₅0_ in solar units. A large class of more general dark matter distributions was also found to be consistent with the data. For these models the range in total mass is larger (1. 1-3. 0) x 10¹5ʰ₅0_^-1^ Mₛun_, and-the mass-to-light ratio varies from 90h₅0_ to 250h₅0_. The ratio of virial mass to X-ray emitting gas mass seems to decrease with radius from the cluster center. The presently available X-ray data have significantly restricted the optically allowed distributions for the virial mass.
John P. Hughes (Wed,) studied this question.