A Dynamical Analysis of the Corona Borealis Supercluster

Abstract

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.

11 pages, 3 figures. To be published in Monthly Notices of the Royal Astronomical Society

References in corpus (3)

• Curvature in the scaling relations of early-type galaxies
• The Fundamental Plane of Early Type Galaxies in Nearby Clusters from the WINGS Database
• Structures in the fundamental plane of early-type galaxies

Cited by in corpus (8)

• Where the world stands still: turnaround as a strong test of ΛCDM cosmology
• Detection of intercluster gas in superclusters using the thermal Sunyaev-Zel'dovich effect
• The Largest Gravitationally Bound Structures: The Corona Borealis Supercluster - Mass and Bound Extent
• Structure and dynamics of the supercluster of galaxies SC0028-0005
• Peculiar Motions of Galaxy Clusters in the Regions of Superclusters of galaxies
• Galaxy clusters as probes for cosmology and dark matter
• Does the Corona Borealis Supercluster form a giant binary-like system?
• The extent of gravitationally bound structure in a ΛCDM universe