# Angular distribution of gamma-ray emission from velocity-dependent dark matter annihilation in subhalos

## TL;DR

This paper analyzes how velocity-dependent dark matter annihilation influences the angular distribution of gamma rays from subhalos, revealing that the emission size and flux normalization are affected differently by halo properties.

## Contribution

It provides a dimensional analysis framework showing how velocity dependence alters gamma-ray emission profiles from dark matter subhalos.

## Key findings

- Angular size of gamma-ray emission is rescaled by a form-dependent factor.
- Flux normalization between subhalos depends on halo parameters.
- Results are applied to NFW profile and subhalo distributions.

## Abstract

We consider the effect of velocity-dependent dark matter annihilation on the angular distribution of gamma rays produced in dark matter subhalos. We assume that the dark matter potential is spherically symmetric, characterized by a scale radius and scale density, and the velocity distribution is isotropic. We find that the effect of velocity-dependent dark matter annihilation is largely determined by dimensional analysis; the angular size of gamma-ray emission from an individual subhalo is rescaled by a factor which depends on the form of the dark matter distribution, but not on the halo parameters, while the relative normalization of the gamma-ray flux from different mass subhalos is rescaled by a factor which depends on the halo parameters, but not on the form of the dark matter distribution. We apply our results to a Navarro-Frenk-White profile for the case of an individual subhalo and comment on the application of these results to a distribution of subhalos.