Stellar and dark matter density in the Local Universe

Abstract

We calculate the mean density profiles for luminous and dark matter on distance scales $D \sim(1 - 100)$ Mpc around us using recent all-sky catalogs of galaxy groups. Within the Local Volume $( D < 11 ~\rm Mpc)$ we derived the mean stellar density $Ω_*= 0.44\%$ in the critical density units and the mean total matter density $Ω_m = 0.17$. In the sphere with a radius of 40 Mpc these quantities drop to $Ω_* = 0.24 - 0.32\%$ and $Ω_m = 0.09 - 0.14$. In a larger volume within $D\sim135$ Mpc the discussed densities become more uncertain: $Ω_* = 0.20 - 0.24\%$ and $Ω_m = 0.05 - 0.16$. We summarize that the major part of the cosmic dark matter locates outside the virial and collapsing zones of groups and clusters.