The Birth and Growth of Neutralino Haloes

Understand

We use the Extended-Press-Schechter (EPS) formalism to study halo assembly histories in a standard $\Lambda$CDM cosmology.

• A large ensemble of Monte Carlo random walks provides the {\it entire} halo membership histories of a representative set of dark matter particles, which we assume to be neutralinos.
• The first generation halos of most particles do not have a mass similar to the free-streaming cut-off $M_{f.s.}$ of the neutralino power spectrum, nor do they form at high redshift.
• Median values are $M_1 = 10^5$ to $10^7M_{f.s.}$ and $z_1 = 13$ to 8 depending on the form of the collapse barrier assumed in the EPS model.