Influence of early dark matter halos on the primordial black holes merger rate

Understand

Primordial black hole (PBH) binaries forming in the early Universe may contribute to the merger events observed by the LIGO-Virgo-KAGRA collaborations.

• Moreover, the inferred merger rate constraints the fraction of PBH with masses $m \sim 10 \, M_{\odot}$ in the dark matter (DM) to $f_{PBH} \lesssim 10^{-3}$.
• This constraint assumes that after the formation of PBH binaries, they do not get destroyed or their parameters are not perturbed until the merger.
• However, PBHs themselves contribute to the formation of early DM structures in which the interactions between PBHs take place actively.