511 keV galactic photons from a dark matter spike
Abstract We propose that a dark matter (DM) spike around the Galactic Center's (GC) supermassive black hole, Sgr A*, could account for most of the bulge's measured 511 keV line intensity while remaining cosmologically compatible. DM annihilation can be the primary source of the 511 keV line emission without violating constraints from disk emission observations and in-flight positron annihilation with the interstellar medium, provided the disk emission is dominated by an astrophysical source of low-energy positrons. We find that a DM mass up to approximately 20 MeV, either with a Gondolo-Silk spike or one softened by stellar heating, could explain the observed 511 keV bulge emission profile. Our proposal can be tested by future observations of the continuum diffuse emission close to the GC.
Authors
- Joseph Silk (ORCID: https://orcid.org/0000-0002-1566-8148)
- S. Balaji (ORCID: https://orcid.org/0000-0002-5364-2109)
- Malcolm Fairbairn (ORCID: https://orcid.org/0000-0002-0566-4127)
- Pedro De la Torre Luque (ORCID: https://orcid.org/0000-0002-4150-2539)
- Filippo Sala (ORCID: https://orcid.org/0000-0001-6565-0862)
Institutions
- Centre National de la Recherche Scientifique (FR)
- Johns Hopkins University (US)
- King's College London (GB)
- Institut d'Astrophysique de Paris (FR)
- Sorbonne Université (FR)
- Ulverscroft (United Kingdom) (GB)
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (IT)
- University of Baltimore (US)
- Universidad Autónoma de Madrid (ES)
- University of Bologna (IT)
Publication Details
- Journal
- Journal of Cosmology and Astroparticle Physics
- Published
- 2025-09-01
- DOI
- https://doi.org/10.1088/1475-7516/2025/09/034
- Citations
- 8
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 9.24