Profiles of dark matter haloes at high redshift

I study the evolution of halo density profiles as a function of time in the SCDM and Lambda CDM cosmologies. Following Del Popolo, I calculate the concentration parameter c = r(v)/a and study its time evolution. For a given halo mass, I find that c(z) proportional to 1/(1 + z) in both the Lambda CDM and SCDM cosmology, in agreement with the analytic model of Bullock et al. and N-body simulations. In both models, a(z) is roughly constant. The present model predicts a stronger evolution of c(z) with respect to the Navarro, Frenk & White model. Finally I show some consequences of the results on galaxy modelling.