Typical density profile for warm dark matter haloes

TL;DR

This paper derives the typical density profiles of warm dark matter haloes, showing they flatten at small radii due to particle velocities, but the core cannot be fully resolved because of protohalo fragmentation.

Contribution

It applies a hierarchical halo growth model to warm dark matter cosmology, predicting flat core profiles influenced by particle velocities.

Findings

Density profiles become flat at small radii.

Core resolution is limited by protohalo fragmentation.

Model invalidates at radii where protohalo fragmentation occurs.

Abstract

Using the model for (bottom-up) hierarchical halo growth recently developed by Salvador-Sol\'e et al. (2012), we derive the typical spherically averaged density profile for haloes with several relevant masses in the concordant warm dark matter (\Lambda WDM) cosmology with non-thermal sterile neutrinos of two different masses. The predicted density profiles become flat at small radii, as expected from the effects of the spectrum cutoff. The core cannot be resolved, however, because the non-null particle velocity yields the fragmentation of minimum mass protohaloes in small nodes, which invalidates the model at the corresponding radii.