Anomalous Ionization in the Central Molecular Zone by sub-GeV Dark Matter

Abstract

We demonstrate that the anomalous ionization rate observed in the Central Molecular Zone can be attributed to MeV dark matter annihilations into $e^{+}{e}^{-}$ pairs for galactic dark matter profiles with slopes $\gamma >1$. The low annihilation cross-sections required avoid cosmological constraints and imply no detectable inverse Compton, bremsstrahlung or synchrotron emissions in radio, X and gamma rays. The possible connection to the source of the unexplained 511 keV line emission in the Galactic Center suggests that both observations could be correlated and have a common origin.

Comments: Contents matching published version: PRL. 134, 101001. Published 10 March, 2025. This includes supp. material too