Peculiar Motions in the Region of the Ursa Major Supercluster of Galaxies - AstrophysicsReport as inadecuate

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Abstract: We have investigated the peculiar motions of clusters of galaxies in the UrsaMajor (UMa) supercluster and its neighborhood. Based on SDSS (Sloan Digital SkySurvey) data, we have compiled a sample of early-type galaxies and used theirfundamental plane to determine the cluster distances and peculiar velocities.The samples of early-type galaxies in the central regions (within R 200) of 12UMa clusters of galaxies, in three main subsystems of the supercluster - thefilamentary structures connecting the clusters, and in nine clusters from thenearest UMa neighborhood have similar parameters. The fairly high overdensity(3 by the galaxy number and 15 by the cluster number) suggests that thesupercluster as a whole is gravitationally bound, while no significant peculiarmotions have been found: the peculiar velocities do not exceed the measurementerrors by more than a factor of 1.5-2. The mean random peculiar velocities ofclusters and the systematic deviations from the overall Hubble expansion in thesupercluster are consistent with theoretical estimates. For the possibleapproach of the three UMa subsystems to be confirmed, the measurement accuracymust be increased by a factor of 2-3.

Author: Flera G. Kopylova, Alexander I. Kopylov (Special Astrophysical Observatory of Russian Academy of Sciences)



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