Galaxy clusters and their outskirts: the "red sequence", star formation rate, stellar mass

Abstract

We study the outskirts ($R<3R_{200c}$) of 40 groups and clusters of galaxies of the local Universe ($0.02<z<0.045$) with 300~km~s$^{-1}<\sigma<950$~km~s$^{-1}$. Using the SDSS DR10 catalog data, we measured the stellar mass of galaxy clusters in accordance with the previously determined $K_s$-luminosity (2MASX data) and found their correlation in the form $M_*/M_{\odot} \propto (L_K/L_{\odot})^{1.010\pm0.004}$ ($M_K<-21\,.\!\!^{\rm m}5$, $R<R_{200c}$). We also found the dependence of the galaxy cluster stellar mass on halo mass: $M_*/M_{\odot} \propto (M_{200c}/M_{\odot})^{0.77\pm0.01}$}. Our results show that the fraction of galaxies with quenched star formation ($M_K<-21\,.\!\!^{\rm m}5$) is maximal in the central regions of the galaxy clusters and equals, on the average, $0.81\pm0.02$; it decreases to $0.44\pm0.02$ outside of the projected radius $R_{sp}$ ($2<R/R_{200c}<3$), which we found from the observed profile, but still remains higher than that in the field by 27\%. The fraction of early-type "red sequence" galaxies decreases from $0.54\pm0.02$ in the center to $0.24\pm0.01$ beyond $R_{\rm sp}$, reaching its field value.