The Dynamics of the Corona Borealis Supercluster

This study of the dynamical properties of the Corona Borealis supercluster is based on a sample of 1555 galaxies in the vicinity of A2061, A2065, A2067, A2079, A2089, and A2092. Photographic R photometry and accurate positional data are available for all galaxies in this sample. Here we include new redshifts for 97 galaxies. The total number of galaxies in the system for which we have redshifts is now 182. Virial masses for the six individual Corona Borealis clusters lie in the range 1.5-8.9 X 10^14^ M_sun_. The central cluster R band luminosity, x-ray luminosity, and surface density are correlated with the cluster velocity dispersion and virial mass. The mean R band mass-to-light ratio in the central 1 Mpc of the clusters is 256 +/- 118. If the galaxy distribution traces the matter distribution, then this result is consistent with {OMEGA}_0_ = 0.2 +/- 0.1. The amount of matter in the supercluster (~ 8.2 X 10^15^ M_sun_) is probably sufficient to bind the system. Dynamical timescales are comparable with the Hubble time, making it unlikely that the system is virialized. Peculiar velocities within the supercluster are <~ 2200 km s^-l^. A large increase in the mass-to-light ratio from the cluster scale of 1 Mpc to scales of 10-20 Mpc is not required to account for the supercluster dynamics. However, such an increase cannot be conclusively ruled out.