Interesting if true. Unfortunately there are just too many sources that can produce ionizing radiation, high energy cosmic rays, energetic positrons etc (especially when you look in at the central part of the MW). So while I wouldn't rule out the explanation, I don't think the paper the paper provides particularly convincing case in favour of DM annihilation explanation vs alternatives.

I was just wondering about this very thing this morning. Nice to see a topical study on it in such a timely fashion.

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