(6d) The Origin and Evolution of Cosmological Halos
Adaptive SPH and N-body simulations were carried out by
Alvarez, Shapiro, & Martel
(
2001a;
[
astro-ph];
2001b)
to study the evolution of the equilibrium structure of dark matter halos
that result from the gravitational instability and fragmentation of
cosmological pancakes. Such halos resemble those formed by hierarchical
clustering from realistic initial conditions in a CDM universe and,
therefore, serve as a test-bed model for studying halo dynamics. The dark
matter density profile is close to the universal halo profile identified
previously from N-body simulations of structure formation in CDM, with a
total mass and concentration parameter which grow linearly with scale factor
a. When gas is included, this concentration parameter is slightly larger
than the pure N-body result. We also find that the dark matter velocity
distribution is less isotropic and more radial than found by N-body
simulations of CDM.