Analysis of the Properties of Clusters of Galaxies in the Region of the Ursa Major Supercluster

TL;DR

This study examines the properties of galaxy clusters within the Ursa Major supercluster using observational data, revealing similarities with other clusters but with less scatter, indicating synchronized evolution.

Contribution

It provides a detailed analysis of galaxy cluster properties in UMa, highlighting their similarities to other clusters and the reduced scatter due to their common origin and evolution.

Findings

UMa clusters have a total mass of 2.25 x 10^15 M_sun.

70% of early-type galaxies are in virialized regions, independent of cluster mass.

Scatter in cluster parameters is smaller in UMa clusters compared to field clusters.

Abstract

We analyze the properties of the clusters of galaxies in the region of the Ursa Major (UMa) supercluster using observational data from SDSS and 2MASS catalogs. The region studied includes a supercluster (with a galaxy and cluster overdensity of 3 and 15, respectively) and field clusters inside the 150 Mpc diameter surrounding region. The total dynamical mass of 10 clusters of galaxies in UMa is equal to 2.25 10^15 M_sun, and the mass of 11 clusters of galaxies in the UMa neighborhood is equal to 1.70 10^15 M_sun. The fraction of early-type galaxies brighter than M_K*+1 in the virialized regions of clusters is, on the average, equal to 70%, and it is virtually independent on the mass of the cluster. The fraction of these galaxies and their average photometric parameters are almost the same both for UMa clusters and for the clusters located in its surroundings. Parameters of the clusters of galaxies, such as infrared luminosities up to a fixed magnitude, the mass-to-luminosity ratio, and the number of galaxies have almost the same correlations with the cluster mass as in other samples of galaxies clusters. However, the scatter of these parameters for UMa member clusters is twice smaller than the corresponding scatter for field clusters, possibly, due to the common origin of UMa clusters and synchronized dynamical evolution of clusters in the supercluster.