The structure of the galaxy cluster A 194.
New radial velocities are presented for 29 galaxies in the Zwicky-Humason field of the cluster Al 94, bringing the total number of known radial velocities in this field to 67. Fifty-seven of these galaxies are members of Al 94. Five galaxies are members of a newly discovered group with an average radial velocity of 7881 km s - The 10 galaxies within the isothermal core radius have a velocity dispersion of 220km 1 The velocity dispersion increases to 530 km -1 at 0?4 (0.75 Mpc) from the cluster center but then levels off or gradually decreases at greater radial distances. As found previously by Zwicky and Humason, the frequency distribution of radial velocities of galaxies in A194 is a Gaussian and the more massive galaxies have a smaller velocity dispersion than the less massive galaxies, indicating an approach toward equipartition of kinetic energy. Adopting conventional mass-tolight ratios for early and late type galaxies, we find that the ratio of virial mass to photographic luminosity for A194 is about 36 solar units (H = 50 km 1 Mpc-1). Subject headings: galaxies: clusters of - galaxies: redshifts
The Astrophysical Journal
- Pub Date:
- June 1977