Possible evidence for MeV dark matter in dwarf spheroidals
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Updated: Aug 21, 2026

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Published on: June 23, 2026
Dan Hooper1, Francesc Ferrer, Céline Boehm
1Astrophysics Department, University of Oxford, Oxford, United Kingdom.
Abstract:
The observed 511 keV emission from the galactic bulge could be due to very light (MeV) annihilating dark matter particles. To distinguish this hypothesis from conventional astrophysical sources, we study dwarf spheroidals in the region observed by the International Gamma-Ray Astrophysics Laboratory/SPI such as Sagittarius. As these galaxies have comparatively few stars, the prospects for 511 keV emission from standard astrophysical scenarios are minimal. The dwarf spheroidals do, however, contain copious amounts of dark matter. The observation of 511 keV emission from Sagittarius should be a "smoking gun" for MeV dark matter.
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