On the Primordial Binary Black Hole Mergings in LIGO-Virgo-Kagra Data

Abstract

We briefly discuss a possible cosmological implication of the observed binary black hole mergings detected by LIGO-Virgo-Kagra collaboration (GWTC-3 catalogue) for the primordial black hole (PBH) formation in the early Universe. We show that the bumpy chirp mass distribution of the LVK BH + BH binaries can be fit with two distinct and almost equal populations: (1) astrophysical mergings from BH + BH formed in the modern Universe from evolution of massive binaries and (2) mergings of binary PBHs with initial log-normal mass distribution. We find that the PBH central mass (\({{M}_{c}} \simeq 30{{M}_{ \odot }}\)) and distribution width derived from the observed LVK chirp masses are almost insensitive to the assumed double PBH formation model. To comply with the observed LVK BH + BH merging rate, the CDM PBH mass fraction should be \({{f}_{{{\text{pbh}}}}} \sim {{10}^{{ - 3}}}\) but can be higher if PBH clustering is taken into account.