Kavli Affiliate: Edmund Bertschinger

| First 5 Authors: Phillip Zukin, Edmund Bertschinger, , ,

| Summary:

Using a generalized self-similar secondary infall model, which accounts for

tidal torques acting on the halo, we analyze the velocity profiles of halos in

order to gain intuition for N-body simulation results. We analytically

calculate the asymptotic behavior of the internal radial and tangential kinetic

energy profiles in different radial regimes. We then numerically compute the

velocity anisotropy and pseudo-phase-space density profiles and compare them to

recent N-body simulations. For cosmological initial conditions, we find both

numerically and analytically that the anisotropy profile asymptotes at small

radii to a constant set by model parameters. It rises on intermediate scales as

the velocity dispersion becomes more radially dominated and then drops off at

radii larger than the virial radius where the radial velocity dispersion

vanishes in our model. The pseudo-phase-space density is universal on

intermediate and large scales. However, its asymptotic slope on small scales

depends on the halo mass and on how mass shells are torqued after turnaround.

The results largely confirm N-body simulations but show some differences that

are likely due to our assumption of a one-dimensional phase space manifold.

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