Dark Matter and Synchrotron Emission from Galactic Center Radio Filaments

TL;DR

This paper proposes that light dark matter particles annihilating in the Galactic center can produce electrons and positrons that account for the observed synchrotron emission from radio filaments, linking it to gamma-ray and direct detection signals.

Contribution

It demonstrates that light dark matter annihilation can explain the synchrotron emission from Galactic center filaments and aligns with gamma-ray and direct detection observations.

Findings

Dark matter annihilation produces electrons/positrons matching filament emission

Dark matter parameters consistent with gamma-ray excess

Dark matter signals align with direct detection experiments

Abstract

The inner degrees of the Galactic center contain a large population of filamentary structures observed at radio frequencies. These so-called non-thermal radio filaments (NRFs) trace magnetic field lines and have attracted significant interest due to their hard (S_v ~ -0.1 +/- 0.4) synchrotron emission spectra. The origin of these filaments remains poorly understood. We show that the electrons and positrons created through the annihilations of a relatively light (~5-10 GeV) dark matter particle with the cross section predicted for a simple thermal relic can provide a compelling match to the intensity, spectral shape, and flux variation of the NRFs. Furthermore, the characteristics of the dark matter particle necessary to explain the synchrotron emission from the NRFs is consistent with those required to explain the excess gamma-ray emission observed from the Galactic center by the Fermi-LAT, as well as the direct detection signals observed by CoGeNT and DAMA/LIBRA.