A. Del Popolo

Density profile slope in Dwarfs and environment

In the present paper, we study how the dark matter density profiles of dwarfs galaxies in the mass range

Density profile slopes of dwarf galaxies and their environment

10^8-10^{10} M_{\odot}

Dark matter, density perturbations, and structure formation

are modified by the interaction of the dwarf in study with the neighboring structures, and by changing baryon fraction in dwarfs. As already shown in Del Popolo (2009), the slope of density profile of inner halos flattens with decreasing halo mass and the profile is well approximated by a Burkerts profile. The analysis shows that dwarfs who suffered a smaller tidal torquing (consequently having smaller angular momentum) are characterized by steeper profiles with respect to dwarfs subject to higher torque, and similarly dwarfs having a smaller baryons fraction have also steeper profiles than those having a larger baryon fraction. In the case tidal torquing is shut down and baryons are not present, the density profile is very well approximated by an Einasto profile, similarly to dwarfs obtained in dissipationless N-body simulations. We then apply the result of the previous analysis to the dark matter halo rotation curves of three different dwarfs, namely NGC 2976, known to have a flat inner core, NGC 5949 having a profile intermediate between a cored and a cuspy one, and NGC 5963 having a cuspy profile. After calculating baryon fraction, which is

On the universality of density profiles

\simeq 0.1

Extended Spherical Collapse and the Accelerating Universe

for the three galaxies, we fitted the rotation curves changing the value of angular momentum. NGC 2976, has an higher value of ordered angular momentum (

Spherical galaxy models as equilibrium configurations in non-extensive statistics

\lambda \simeq 0.04

Shear and rotation in Chaplygin cosmology

) with respect to NGC 5949 (

Secondary infall model and dark matter scaling relations in intermediate-redshift early-type galaxies

\lambda \simeq 0.025

A theoretical study of the mass–temperature relation for clusters of galaxies

) and in the case of NGC 5963 the very steep profile can be obtained with a low value of

On the reliability of merger-trees and the mass growth histories of dark matter haloes

\lambda