  There is no accepted mechanism that explains the equilibrium structures that
form in collisionless cosmological N-body simulations. Recent work has
identified nonextensive thermodynamics as an innovative approach to the
problem. The distribution function that results from adopting this framework
has the same form as for polytropes, but the polytropic index is now related to
the degree of nonextensiveness. In particular, the nonextensive approach can
mimic the equilibrium structure of dark matter density profiles found in
simulations. We extend the investigation of this approach to the velocity
structures expected from nonextensive thermodynamics. We find that the
nonextensive and simulated N-body rms-velocity distributions do not match one
another. The nonextensive rms-velocity profile is either monotonically
decreasing or displays little radial variation, each of which disagrees with
the rms-velocity distributions seen in simulations. We conclude that the
currently discussed nonextensive models require further modifications in order
to corroborate dark matter halo simulations. (adapted from TeX)
