Profiles of dark haloes: evolution, scatter and environment

摘要: We study dark-matter halo density profiles in a high-resolution N-body simulation of aCDM cosmology. Our statistical sample contains �5000 haloes the range 10 11 14 h −1 M⊙ and resolution allows subhaloes inside host haloes. The are parameterized by an NFW form with two parameters, inner radius rs virial Rvir, we define concentration cvirRvir/rs. find that, for given mass, redshift dependence median is cvir / (1 + z) . This corresponds to rs(z) � constant, contrary earlier suspicions that does not vary much redshift. implications high- galaxies predicted be more extended dimmer than expected before. Second, scatter large, 1� �(logcvir) = 0.18 at corresponding maximum rotation velocities �Vmax/Vmax 0.12. discuss modelling Tully-Fisher relation, which has smaller reported intrinsic scatter. Third, dense environments tend concentrated isolated haloes, show larger These results suggest essential parameter theory galaxy modelling, briefly universality Tully- Fisher formation low surface brightness galaxies, origin Hubble sequence. present improved analytic treatment fits measured relations between parameters their dependence, can thus serve semi-analytic studies formation.