Yale Astronomy Seminar - Nick Esser

Primordial black holes (PBHs) are theoretical black holes formed in the early Universe that could account for all of the dark matter (DM) if their masses lie within the so-called “asteroid-mass” range. In this talk, I will present the first observation-based constraints on PBHs in this previously open asteroid-mass window. These constraints are based on the capture of PBHs by stars in the DM–dominated environments of ultra-faint dwarf (UFD) galaxies, and on the subsequent impact of this process on the stellar mass function of these galaxies. I will review the capture mechanism of PBHs by stars, the accretion of stars by the PBHs they have captured, the resulting effect on the stellar mass function of UFDs, and how the non-observation of this effect in Hubble Space Telescope photometric data has been used to place constraints on these primordial black holes.

This talk is based on the following papers: Phys. Rev. D 2207.07412, MNRAS 2311.12658, and A&A 2503.03352.