Detectability of dark matter subhalos by means of the GAMMA-400 telescope

TL;DR

This study assesses the potential of the GAMMA-400 telescope to detect gamma-ray signals from dark matter subhalos, highlighting the dependence on WIMP properties and the challenges in resolving subhalo structures.

Contribution

It provides a simulation-based analysis of dark matter subhalo detectability with GAMMA-400, considering flux predictions and the likelihood of identifying specific subhalo candidates.

Findings

Expected gamma-ray flux from subhalos could be detectable by GAMMA-400.

Resolving subhalo inner structures likely requires combined data analysis.

Certain subhalo candidates are unlikely to be actual dark matter subhalos.

Abstract

We investigated the detectability of Galactic subhalos with masses $(10^6-10^9)M_{\odot}$ formed by annihilating WIMP dark matter by the planned GAMMA-400 gamma-ray telescope. The inner structure of dark matter subhalos and their distribution in the Galaxy were taken from corresponding simulations. We showed that the expected gamma-ray flux from subhalos strongly depends on WIMP mass and subhalo concentration, but less strongly depends on the subhalo mass. In an optimistic case we may expect the flux of 10-100 ph/year above 100 MeV from the closest and most massive subhalos, which would be detectable sources for GAMMA-400. However, resolving the inner structure of subhalos might be possible only by the joint analysis of the future GAMMA-400 data and data from other telescopes due to smallness of fluxes. Also we considered the recent subhalo candidates 3FGL J2212.5+0703 and J1924.8-1034 within the framework of our model. We concluded that it is very unlikely that these sources belong to the subhalo population.