Primordial Black Holes as Dark Matter Candidates

Understand

We review the formation and evaporation of primordial black holes (PBHs) and their possible contribution to dark matter.

• Various constraints suggest they could only provide most of it in the mass windows $10^{17}$ - $10^{23}\,$g or $10$ - $10^{2}\,M_{\odot}$, with the last possibility perhaps being suggested by the LIGO/Virgo observations.
• However, PBHs could have important consequences even if they have a low cosmological density.
• Sufficiently large ones might generate cosmic structures and provide seeds for the supermassive black holes in galactic nuclei.