2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/14979I apply the modified spherical infall model to test the dependence of the shape of density profiles of dark matter halos on redshift. The model predicts that the density profile of a halo of a given mass steepens with time and its concentration parameter changes like c~1/(1+z_0)^2.2 pages, 1 figure, contribution to the Proceedings of Rencontres Internationales de l'IGRAP, Clustering at High Redshift, Marseille 1999, in pressAstrophysicstext