Surface Density of dark matter haloes on galactic and cluster scales
  In this paper, in the framework of the secondary infall model, the
correlation between the central surface density and the halo core radius of
galaxy, and cluster of galaxies, dark matter haloes was analyzed, this having
recently been studied on a wide range of scales. We used Del Popolo (2009)
secondary infall model taking into account ordered and random angular momentum,
dynamical friction, and dark matter (DM) adiabatic contraction to calculate the
density profile of haloes, and then these profiles are used to determine the
surface density of DM haloes. The main result is that $r_\ast$ (the halo
characteristic radius) is not an universal quantity as claimed by Donato et al.
(2009) and Gentile et al. (2009). On the contrary, we find a correlation with
the halo mass $M_{200}$ in agreement with Cardone & Tortora (2010), Boyarsky at
al. (2009) and Napolitano et al. (2010), but with a significantly smaller
scatter, namely $0.16 \pm 0.05$. We also consider the baryon column density
finding this latter being indeed a constant for low mass systems such as
dwarfs, but correlating with mass with a slope $\alpha= 0.18 \pm 0.05$. In the
case of the surface density of dark matter for a system composed only of dark
matter, as in dissipationless simulations, we get $\alpha=0.20 \pm 0.05$. These
results leave little room for the recently claimed universality of (dark and
stellar) column density.
