ASTROPHYSICS, SPACE PHYSICS, COSMOLOGY, GRAVITATION

On the increase in the density of primordial black holes in the halos of dwarf galaxies

S. V. Pilipenko, M. V. Tkachev, N. R. Arakelyan

Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 117997 Russia

Abstract: Through numerical experiments, we have predicted that if dark matter contains even a small fraction, ${{f}_{0}} \sim {{10}^{{ - 4}}}$, of primordial black holes (PBHs), during the formation of the gravitationally bound halo of a dwarf galaxy, these PBHs will concentrate in a region with a radius of about 10 pc, so that their local fraction will exceed 1%. Unlike previous studies of PBH migration to the centers of galaxies, the numerical experiments conducted here take into account the early formation of a massive “dress” of dark matter around the PBHs and the non-stationarity of the halo during its formation. Applying our results to models of heating stellar clusters in the Eridanus II and Segue I galaxies due to dynamical friction between stars and PBHs allows us to impose constraints on the abundance of PBHs that are two orders of magnitude stricter than previously thought.

Received: 15.11.2024
Revised: 20.01.2025
Accepted: 20.01.2025

DOI: 10.31857/S0370274X25030033

 English version: Journal of Experimental and Theoretical Physics Letters, 2025, 121:5, 324–331