Primordial Black Holes Excluded As Dark Matter Candidate

We model the accretion of gas on to a population of massive primordial black holes in the Milky Way, and compare the predicted radio and X-ray emission with observational data. We show that under conservative assumptions on the accretion process, the possibility that O(10)M⊙ primordial black holes can account for all of the dark matter in the Milky Way is excluded at 4σ by a comparison with the VLA radio catalog at 1.4 GHz, and at more than 5σ by a comparison with the NuSTAR X-ray catalog (10 - 40 keV). We also propose a new strategy to identify such a population of primordial black holes with more sensitive future radio and X-ray surveys.

Daniele Gaggero, et al., "Searching for Primordial Black Holes in the radio and X-ray sky" (Pre-Print December 1, 2016).

There has been strong evidence disfavoring primordial black holes (i.e. black holes created at the dawn of the universe, rather than by stellar collapse and accretion of new matter) as a candidate for the main component of dark matter for a long time. This paper really seals the deal.