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.

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

References in corpus (19)

• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• Herschel Survey of Galactic OH+, H2O+, and H3O+: Probing the Molecular Hydrogen Fraction and Cosmic-Ray Ionization Rate
• Spatial distribution of interstellar gas in the innermost 3 kpc of our Galaxy
• Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients
• Refined Bounds on MeV-scale Thermal Dark Sectors from BBN and the CMB
• BBN And The CMB Constrain Neutrino Coupled Light WIMPs
• An Improved Limit on Invisible Decays of Positronium
• The Origin of Diffuse X-ray and $\gamma$-ray Emission from the Galactic Center Region: Cosmic Ray Particles
• Continuum gamma-ray emission from light dark matter positrons and electrons
• APEX mapping of H3O+ in the Sgr B2 region
• Infrared H3+ and CO Studies of the Galactic Core: GCIRS 3 and GCIRS 1W
• The Positron Puzzle
• Supernova bounds on axion-like particles coupled with nucleons and electrons
• Signature of Energy Losses on the Cosmic Ray Electron Spectrum
• 511 keV line constraints on feebly interacting particles from supernovae
• Imaging the 511 keV positron annihilation sky with COSI
• Resonant or asymmetric: The status of sub-GeV dark matter
• A study of methanol and silicon monoxide production through episodic explosions of grain mantles in the Central Molecular Zone
• Cosmic rays cannot explain the high ionisation rates in the Galactic centre

Cited by in corpus (4)

• Dark Matter in X-rays: Revised XMM-Newton Limits and New Constraints from eROSITA
• Sub-keV dark matter can strongly ionize molecular clouds
• Absorption of Fermionic Dark Matter in the PICO-60 C${}_3$F${}_8$ Bubble Chamber
• Diffuse continuum emission and large extended sources at MeV energies