Shocking Signals of Dark Matter Annihilation

TL;DR

This paper investigates whether dark matter annihilation products can be accelerated to high energies in astrophysical shocks, potentially explaining features in cosmic rays and radio emissions in various cosmic environments.

Contribution

It introduces the idea that dark matter annihilation products can be accelerated in shock regions, highlighting Fermi bubbles as efficient accelerators and predicting observable signals.

Findings

Dark matter annihilation can produce a spectral bump in cosmic rays.

Fermi bubbles are more efficient accelerators than supernova remnants.

Acceleration of dark matter products could explain enhanced radio emissions and anti-deuteron fluxes.

Abstract

We examine whether charged particles injected by self-annihilating Dark Matter into regions undergoing Diffuse Shock Acceleration (DSA) can be accelerated to high energies. We consider three astrophysical sites where shock acceleration is supposed to occur, namely the Galactic Centre, galaxy clusters and Active Galactic Nuclei (AGN). For the Milky Way, we find that the acceleration of cosmic rays injected by dark matter could lead to a bump in the cosmic ray spectrum provided that the product of the efficiency of the acceleration mechanism and the concentration of DM particles is high enough. Among the various acceleration sources that we consider (namely supernova remnants (SNRs), Fermi bubbles and AGN jets), we find that the Fermi bubbles are a potentially more efficient accelerator than SNRs. However both could in principle accelerate electrons and protons injected by dark matter to very high energies. At the extragalactic level, the acceleration of dark matter annihilation products could be responsible for enhanced radio emission from colliding clusters and prediction of an increase of the anti-deuteron flux generated near AGNs.