Relaxation of dark matter halos: how to match observational data?
  We show that moderate energy relaxation in the formation of dark matter halos
invariably leads to profiles that match those observed in the central regions
of galaxies. The density profile of the central region is universal and
insensitive to either the seed perturbation shape or the details of the
relaxation process. The profile has a central core; the multiplication of the
central density by the core radius is almost independent of the halo mass, in
accordance with observations. In the core area the density distribution behaves
as an Einasto profile with low index ($n\sim 0.5$); it has an extensive region
with $\rho\propto r^{-2}$ at larger distances. This is exactly the shape that
observations suggest for the central region of galaxies. On the other hand,
this shape does not fit the galaxy cluster profiles. A possible explanation of
this fact is that the relaxation is violent in the case of galaxy clusters;
however, it is not violent enough when galaxies or smaller dark matter
structures are considered. We discuss the reasons for this.
