On the self-confinement of electrons and positrons injected by dark matter

July 4 – 8, 2022

Dark matter particles with mass in the GeV-TeV regime can inject fluxes of primary and secondary high-energy electrons and positrons through annihilation or decay. Emitted in regions with an ambient magnetic field at the microGauss level, such electrons and positrons give raise to a synchrotron radiation peaked in the radio band. At the same time, they can undergo inverse Compton scattering with the interstellar radiation field generating an emission in the X- and gamma-ray bands. Such electromagnetic signatures are potentially detectable. The shape of the signal, as well as the amount of energy that is radiated away by the electrons and positrons before escaping the object, depends on their spatial diffusion. This process can be described in terms of scattering with random hydromagnetic waves, and the generation of magnetic turbulence is typically associated to supernovae activity.
In objects where the star formation is low or absent, as e.g. in ultra-faint dwarf spheroidal galaxies, there is no guaranteed confinement of cosmic-ray particles. As an alternative, in this project we will investigate the possibility that, if dark matter is injecting a sizable amount of electrons and positrons, they can themselves induce irregularities in the magnetic field, thus leading to a certain level of spatial confinement.

Project proponent:

  • Marco Regis (University of Torino)

List of participants:

  • Michael Korsmeier (Stockholm University)
  • Marco Regis (University of Torino)
  • Javier Reynoso-Cordova (University of Torino)
  • Piero Ullio (SISSA)