Galaxy Cluster A 2142: Halo Boundary, “Red Sequence”, Properties of Galaxies Based on SDSS

—Here we present results of studying the dynamics of galaxies, properties of early-type galaxies, properties of galaxies with the quenched star formation (QGs) in the A 2142 cluster based on the archival data from the Sloan Digital Sky Survey Data (SDSS DR10). We found the observed halo boundary, the “splashback” radius R_sp , which is equal to 4.12 Mpc ( M_r < - 20.^m3 ) and 4.06 Mpc ( M_r < - 21.^m5 ) over the integral distribution of the number of galaxies as a function of the squared distance from the center. We have studied how early-type galaxies are distributed in the center and in the outskirts of the cluster ( R / . -0emR_200 < 3, M_r < - 20.^m3 ) and plotted the “red sequence” in the form of (g - r) = ( - 0.024 ± 0.001)M_r + (0.441 ± 0.005) . Among all the cluster galaxies, the galaxies with the quenched star formation ( - 12 yr ^ - 1 < log sSFR < 10.75 yr ^ - 1 ) make up about one third. We have found that the fraction of QGs beyond the “splashback” radius R_sp is the same as in the field at the same z with coordinates of the center of 16.^h5, 31 ° and a size of 300′. For galaxies with the stellar masses logM_*/ . -0emM_⊙ = [10.5;11.0] (this is the main mass range of QGs), when entering the cluster, there is a decrease in the radii R_90,r by about 30% when moving towards the center.