Rich Galaxy Clusters from CfA2 Redshift Survey: Spatial Dynamic and High-Energy Gamma-Emission

Abstract

Preliminary results of the investigation of the characteristics of 5 groups of galaxies are discussed in the presented article. We have analyzed the main characteristics of galaxy clusters 933, 88, 142, 1046, 1101 from CfA2 redshift survey. Clusters 933, 142, 1046, and 1652 have high-energy gamma associations on Fermi/LAT data (4FGL J1144.9 $$+$$ 1937, 4FGL J0152.2 $$+$$ 3714, 4FGL J1230.8 $$+$$ 1223 and 4FGL J1653.8 $$+$$ 3945). These sources are active galaxies. Furthermore, the radiogalaxy 3C 264 (4FGL J1144.9 $$+$$ 1937) was previously observed in the energy band $$E>1$$ TeV. We have found several anomalies of the spatial dynamics of galaxies in these clusters. These features could be caused by the dynamics of galaxies’ motion in a gravitationally bound group taking into account possible space–time inhomogeneities at large distances. Investigation of high-energy gamma-emission of galaxies and peculiarities of its motion in groups allows studying properties of such inhomogeneities and understanding of its nature possibly caused by dark matter. The investigation of the spatial distribution and other characteristics of 933, 88, 142, 1046, 1101 galaxy clusters shows gravitational lensing effect. But now it is unknown which objects are gravitational lenses for these clusters. The angular size of such clusters is about 1–2 degree and now there are not clear associations between group members of clusters 142, 1046, and 1652 with the high-energy gamma-sources 4FGL J0152.2 $$+$$ 3714, 4FGL J1230.8 $$+$$ 1223, and 4FGL J1653.8 $$+$$ 3945. Common observations of such clusters by orbital gamma-ray observatories with high angular resolution and ground-based Cherenkov air-shower experiments could possibly clarify the type of gravitational lenses.