Gravitational Accretion of Hot Dark Matter
Abstract
A major difficulty with hot dark matter models, namely their extremely large clustering scales ~10^15^ M_sun_, can be alleviated by allowing dark matter to accrete onto a perturbing mass in the course of galaxy formation. The perturbing mass must not be itself composed of dark matter, but could be a concentration of baryons, a cosmic string loop, or some other massive object. A simulation using 1.25 x 10^5^ particles in an N-body model indicates that such accretion can produce a system similar to observed galactic halos, with a power-law density function ρ(r) proportional to r^-β^, where β= 2.05 +/- 0.05. This is a closer fit to the behavior of actual dark halos than any available cold dark matter model produces. If the initial perturbation has mass M_p_ ~ 5 x 10^9^ M_sun_, the circular velocity for stable orbits is V_c_(r) ~ 250 km (s)^-1^ at 5-10 kpc radius and remains almost constant to a radius of R(halo) ~ 320 kpc, which is a reasonable fit for a large isolated spiral galaxy.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1988
- DOI:
- 10.1086/185165
- Bibcode:
- 1988ApJ...329L...5D
- Keywords:
-
- Astronomical Models;
- Dark Matter;
- Galactic Evolution;
- Mass Distribution;
- Baryons;
- Galactic Clusters;
- Many Body Problem;
- Monte Carlo Method;
- Astrophysics;
- COSMOLOGY;
- DARK MATTER;
- GALAXIES: CLUSTERING;
- GALAXIES: FORMATION;
- GRAVITATION