Properties of galaxy clusters in cosmologies with dark energy

We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and compare them with "standard" \u39bCDM and OCDM models. The dependence of averaged halo concentrations on mass and redshift permits a simple fit of the form (1+z)c=c0(M/M0)\u3b1, with \u3b1 48-0.1 throughout. We find that the cluster concentration depends on the dark energy equation of state at the cluster formation redshift zcoll through the linear growth factor D+(zcoll). As a simple correction accounting for dark-energy cosmologies, we propose scaling c0 from \u39bCDM with the ratio of linear growth factors, c0\u2192c0D+(zcoll)/D+,\u39bCDM(zcoll)