New Form of Dark Matter Could Solve Decades-Old Milky Way Mystery
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Summary
Astronomers have struggled to understand two curious phenomena at the heart of the Milky Way: why the gas in the central molecular zone (CMZ) is highly ionized and why telescopes detect a mysterious glow of gamma rays of exactly 511 kilo-electronvolts (keV).
In a study published in Physical Review Letters, Shim Balaji and colleagues at King’s College London proposed that these two puzzles could be caused by the same process: dark matter.
In particular, they suggest that dark matter particles less than a giga electronvolt (sub-GeV or light dark matter) could be interacting with their antimatter counterparts in the galactic centre, creating electrons and positrons.
These would quickly lose their energy in the dense gas of the CMZ, explaining the high ionization rates.
Eventually, when the electrons and positrons annihilate, they would produce the mysterious glow of gamma rays, solving this puzzle too.
