Dark energy and key physical parameters of clusters of galaxies

Abstract

We study physics of clusters of galaxies embedded in the cosmic dark energy background. The equilibrium and stability of polytropic spheres with equation of state of the matter P = Kργ, γ = 1 + 1/n, in presence of a non-zero cosmological constant Λ is investigated. The equilibrium state exists only for central densities ρ0 larger than the critical value ρc and there are no static solutions at ρ0