A Dynamical Analysis of the Corona Borealis Supercluster
  Using data from the Sloan Digital Sky Survey we assess the current dynamical
state of the Corona Borealis Supercluster (CSC), a highly dense and compact
supercluster at z = 0.07. The Fundamental Plane relation is used to determine
redshift independent distances to six clusters in the densest region of the
supercluster, with mean accuracy in the relative distance estimates of 4 per
cent. Peculiar velocities determined from these distance estimates indicate
that the clusters have broken from the Hubble Flow, suggesting that the CSC
likely contains two regions that have reached turnaround and are currently
undergoing gravitational collapse. These results provide the strongest
observational evidence to date that the CSC is a bound system similar to the
much more extensive Shapley Supercluster, which is the most extensive confirmed
bound supercluster yet identified in the Universe. When compared with
simulations of the CSC our results require substantially more mass than is
contained within the clusters, possibly indicating a significant inter-cluster
dark matter component. In order to facilitate comparison with studies for which
spectroscopic data are not available, an alternative analysis of the dynamics
is made using the Kormendy relation as a distance indicator. The results are
generally consistent with those of the Fundamental Plane and suggest similar
global dynamics, but we find that the relatively sparse sampling of the
clusters makes the Kormendy relation less reliable overall and more susceptible
to small systematic differences between the cluster samples.
