## Theoretical dark matter halo density profile    [PDF]

Eduard Salvador-Solé, Jordi Viñas, Alberto Manrique, Sinue Serra
We present a model of density profile for collisionless dissipationless dark matter haloes in hierarchical cosmologies based on the classical secondary infall approach. The novelties are: i) we deal with triaxial systems; ii) the seeds are assumed to be peaks with their accurate spherically averaged {\it unconvolved} density profile; iii) the initial peculiar velocities are taken into account; and iv), as accurately checked against simulations, accreting haloes are assumed to develop from the inside out, keeping the instantaneous inner system unaltered. We show that the spherically averaged density profile is insensitive to the triaxial shape of haloes and can be directly inferred, down to any arbitrarily small radius, from the power-spectrum of density perturbations. The inner asymptotic logarithmic slope of the density profile predicted in the $\Lambda$CDM is null, although this limit is approached very slowly. Down to one hundredth the virial radius, the profile has the right NFW form but it is even better fitted by the Einasto profile, which gives an acceptable fit down to a radius four orders of magnitude less. Even if the model assumes pure accretion, it is shown to hold for all haloes regardless of their aggregation history. The present results fully justify the peak formalism for halo statistics relying on the secondary infall model.
View original: http://arxiv.org/abs/1104.2334