Is the Concentration of Dark Matter Halos at Virialization Universal ?

Understand

Several recent studies suggest a correlation between dark matter halo mass and the shape of the density profile.

• We re-analyze simulations from Ricotti (2003) in which such a correlation was proposed.
• We use a standard analysis of the halo density profiles and compare the old simulations to new ones performed with Gadget2, including higher resolution runs.
• We confirm Ricotti's result that, at virialization, the central log slopes alpha, at 5%-10% of the virial radius are correlated with the halo mass and that the halo concentration is a universal constant.