Effect of dark matter halo substructures on galaxy rotation curves

TL;DR

This paper models how dark matter halo substructures influence galaxy rotation curves, revealing significant effects and predicting NFW-like profiles through a self-similar, fractal-based approach.

Contribution

It introduces a self-similar, fractal-based model of dark matter halos to analyze their impact on galaxy rotation curves, incorporating halo substructures.

Findings

Halo substructures significantly affect galaxy velocity fields.

The model predicts NFW-like rotation curves.

A scale-free power spectrum of velocity fluctuations is derived.

Abstract

The effect of halo substructures on galaxy rotation curves is investigated in this paper using a simple model of dark matter clustering. A dark matter halo density profile is developed based only on the scale free nature of clustering that leads to a statistically self-similar distribution of the substructures at galactic scale. Semi-analytical method is used to derive rotation curves for such a clumpy dark matter density profile. It is found that the halo substructures significantly affect the galaxy velocity field. Based on the fractal geometry of the halo, this self-consistent model predicts an NFW-like rotation curve and a scale free power spectrum of the rotation velocity fluctuations.