The mean redshift of the core of the Coma cluster-cz = 6953 km s −1 and its dispersion σ = 949 km s −1 are obtained by means of the analysis of the substructures of this cluster by using the S-tree method. The existence of three subgroups of galaxies is revealed, one of them is associated with the cD galaxy NGC 4874, the other – with NGC 4889. It is argued that these subgroups are galaxy associ...

We develop a theory of convex cocompact subgroups of the mapping class group MCG of a closed, oriented surface S of genus at least 2, in terms of the action on Teichmüller space. Given a subgroup G of MCG de ning an extension 1 ! 1(S) ! ΓG ! G ! 1, we prove that if ΓG is a word hyperbolic group then G is a convex cocompact subgroup of MCG. When G is free and convex cocompact, called a Schottky ...

in present study the zoonotic role of cat in bartonella henselae transmission have determined. it has done on 100 cats in 2 groups: indoor and outdoor and in 2 age's subgroups. bartonella henselae was not isolated from blood culture of cats. 23 cats from 100 cats (23%) had antibodies against b. henselae. in this study there were no significant differences statistically in seroprevalence be...

we call $h$ an $ss$-embedded subgroup of $g$ if there exists a‎ ‎normal subgroup $t$ of $g$ such that $ht$ is subnormal in $g$ and‎ ‎$hcap tleq h_{sg}$‎, ‎where $h_{sg}$ is the maximal $s$-permutable‎ ‎subgroup of $g$ contained in $h$‎. ‎in this paper‎, ‎we investigate the‎ ‎influence of some $ss$-embedded subgroups on the structure of a‎ ‎finite group $g$‎. ‎some new results were obtained.

VLT1 spectroscopic observations of Lyα-excess objects in the field of the clumpy radio galaxy 1138–262 at z = 2.16 have led to the discovery of 14 galaxies and one QSO at approximately the same distance as the radio galaxy. All galaxies have redshifts in the range 2.16±0.02, centered around the redshift of the radio galaxy, and are within a projected physical distance of 1.5 Mpc from it. The ve...

In recent years, starting with the paper [B-D-S], we have investigated the possibility of characterizing countable subgroups of the torus T = R/Z by subsets of Z. Here we consider new types of subgroups: let K ⊆ T be a Kronecker set (a compact set on which every continuous function f : K → T can be uniformly approximated by characters of T ), and G the group generated by K. We prove (Theorem 1)...