Coalescing primordial binary black holes with log-normal mass spectrum

Abstract

Primordial black holes created in the early Universe can constitute a substantial fraction of dark matter and serve as seeds for early galaxy formation. Binary primordial black holes with masses of the order of a few dozen solar masses can explain the observed LIGO/Virgo gravitational-wave events. In this Letter, we show that primordial black holes with log-normal mass spectrum centered at $M_0\simeq 15-17M_{\odot }$ simultaneously explain both the chirp mass distribution of the detected LIGO/Virgo binary black holes and the differential chirp mass distribution of merging binaries as inferred from the LIGO/Virgo observations. The obtained parameters of log-normal mass spectrum of primordial black holes also give the fraction of seeds with $M\gtrsim 10^4{M}_{\odot }$ required to explain the observed population of supermassive black holes at $z=6-7$.

4 pages, 2 figures, to be submitted