17–20 Jun 2024
National Galleries of Scotland
Europe/London timezone

Constraints on Primordial Black Holes From Stars in Ultra-Faint Dwarf Galaxies

17 Jun 2024, 12:00
10m
National Galleries of Scotland

National Galleries of Scotland

The Mound, Edinburgh, EH2 2EL Scotland

Speaker

Nicolas Esser (Université Libre de Bruxelles (ULB), Theoretical Physics Group (PhysTH))

Description

If primordial black holes (PBHs) constitute the dark matter (DM), stars forming in dark-matter dominated environments with low velocity dispersions, such as ultra-faint dwarf galaxies, may capture a black hole at birth. The capture probability is non-negligible for PBHs of masses around $10^{20}$g, and increases with stellar mass. Moreover, infected stars are turned into virtually invisible black holes on cosmologically short time-scales. Hence, the number of observed massive main-sequence stars in ultra-faint dwarfs should be suppressed if the DM was made of asteroid-mass PBHs. This would impact the measured mass distribution of stars, making it top-light (i.e. depleted in the high-mass range). Using simulated data that mimic the present-day observational power of telescopes, we show that already existing measurements of the mass function of stars in local ultra-faint dwarfs could be used to constrain the fraction of DM composed of PBHs in the - currently unconstrained - mass range of $10^{19}$ - $10^{21}$g.

Primary authors

Nicolas Esser (Université Libre de Bruxelles (ULB), Theoretical Physics Group (PhysTH)) Petr Tinyakov (Universite Libre de Bruxelles (ULB)) Prof. Sven De Rijcke (Ugent)

Presentation materials