Using spectroscopic and CCD photometric observations on the 6 m and 1 m telescopes of SAO RAS the spatial structure of the apparently compact superclusters Ursa Major and Corona Borealis is determined. Rc-band Kormendy relation (μe = A×log(Re)+C) is employed for measurement of the relative distances of clusters along the line of sight. The Ursa Major supercluster, having a velocity spread of 6000 km/s, on the whole obeys the Hubble dependence between radial velocity and distance, but is not a supermassive system with a large amount of "hidden" matter. Being stretched along the line of sight the supercluster consists possibly of two associations of clusters with mean velocities of 16200 and 19700 km/s. These subsystems are probably gravitationally bound with internal dynamical velocities not exceeding 1100 km/s. Analysis of Hubble diagram of the Corona Borealis supercluster indicates that this system is one of rare in the present epoch extremely massive and dynamically active superclusters. It is likely that the compact core of the system, which is made up of five rich clusters, due to its high mass density has overcome the global expansion of the Universe and is in a stage of rapid gravitational collapse.
Bulletin of the Special Astrophysics Observatory
- Pub Date:
- Galaxies: Clusters: General;
- Galaxies: Kinematics and Dynamics