The distribution of annihilation luminosities in dark matter substructure

TL;DR

This paper models the probability distribution of dark matter subhalo annihilation luminosities, revealing significant variability that impacts gamma-ray signal predictions and the interpretation of dark matter detection efforts.

Contribution

It introduces a semi-analytical approach to quantify the luminosity distribution of dark matter subhalos based on mass and location, aiding in more accurate gamma-ray signal modeling.

Findings

Luminosity PDFs are broad, with up to an order of magnitude spread.

The model enables creation of mock gamma-ray subhalo samples.

Variance in luminosities affects dark matter detection and astrophysical background assessments.

Abstract

We calculate the probability distribution function (PDF) of the expected annihilation luminosities of dark matter subhalos as a function of subhalo mass and distance from the Galactic center using a semi-analytical model of halo evolution. We find that the PDF of luminosities is relatively broad, exhibiting a spread of as much as an order of magnitude at fixed subhalo mass and halo-centric distance. The luminosity PDF allows for simple construction of mock samples of gamma-ray luminous subhalos and assessment of the variance in among predicted gamma-ray signals from dark matter annihilation. Other applications include quantifying the variance among the expected luminosities of dwarf spheroidal galaxies, assessing the level at which dark matter annihilation can be a contaminant in the expected gamma-ray signal from other astrophysical sources, as well as estimating the level at which nearby subhalos can contribute to the antimatter flux.