The self-confinement of electrons and positrons from dark matter

Abstract

Radiative emissions from electrons and positrons generated by dark matter (DM) annihilation or decay are one of the most investigated signals in indirect searches of WIMPs. Ideal targets must have large ratio of DM to baryonic matter. However, such ``dark'' systems have a poorly known level of magnetic turbulence, which determines the residence time of the electrons and positrons and therefore also the strength of the expected signal. This typically leads to significant uncertainties in the derived DM bounds. In a novel approach, we compute the self-confinement of the DM-induced electrons and positrons. Indeed, they themselves generate irregularities in the magnetic field, thus setting a lower limit on the presence of the magnetic turbulence. We specifically apply this approach to dwarf spheroidal galaxies. Finally, by comparing the expected synchrotron emission with radio data from the direction of the Draco galaxy collected at the Giant Metre Radio Telescope, we show that the proposed approach can be used to set robust and competitive bounds on WIMP DM.

18 pages, 10 figures. v2: minor revision, matches published version

References in corpus (11)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• Spectral breaks as a signature of cosmic ray induced turbulence in the Galaxy
• Multi-wavelength signals of dark matter annihilations at the Galactic center
• Bayesian analysis of resolved stellar spectra: application to MMT/Hectochelle Observations of the Draco dwarf spheroidal
• Self-Generated Cosmic-Ray Turbulence Can Explain the Morphology of TeV Halos
• Local Group dSph radio survey with ATCA (III): Constraints on Particle Dark Matter
• Local Group dSph radio survey with ATCA (II): Non-thermal diffuse emission
• Grammage of cosmic rays in the proximity of supernova remnants embedded in a partially ionized medium
• Stringent constraint on the radio signal from dark matter annihilation in dwarf spheroidal galaxies using the TGSS
• Upper limits on the dark matter content in globular clusters
• Weakly interacting massive particle cross section limits from LOFAR observations of dwarf spheroidal galaxies

Cited by in corpus (2)

• WIMP constraints from black hole low-mass X-ray binaries
• WIMP Dark Matter Searches in Reticulum II Using MeerKAT