Effect of small scale density perturbations on the formation of dark matter halo profiles

TL;DR

This study uses toy N-body models to investigate how small scale initial density perturbations influence the inner density profiles of dark matter haloes, revealing potential causes for cuspless galactic haloes.

Contribution

It demonstrates that small scale perturbations can significantly flatten the inner density slope of dark matter haloes, a novel insight into halo profile formation.

Findings

Inner slope flattened to -0.5 with perturbations

Absence of perturbations reproduces NFW profile with slope -1

Small scale perturbations may explain cuspless galactic haloes

Abstract

With help of a set of toy N-body models of dark halo formation we study the impact of small scale initial perturbations on the inner density profiles of haloes. We find a significant flattening of the inner slope $\alpha={d \log \rho \over d \log r}$ to $\alpha=-0.5$ in some range of scales and amplitudes of the perturbations (while in the case of absence of these perturbations the NFW profile with $\alpha=-1$ is reproduced). This effect may be responsible for the formation of cuspless galactic haloes.