Search

Available data on the chirp mass distribution of the coalescing black hole binaries in O1-O3 LIGO/Virgo runs are analyzed and compared statistically with the distribution calculated under the assumption that these black holes are primordial with a log-normal mass spectrum. The theoretically calculated chirp mass distribution with the inferred best acceptable mass spectrum parameters, $M_0=17 M_\odot$ and $\gamma=0.9$, perfectly describes the data. The value of $M_0$ very well agrees with the theoretically expected one. On the opposite, the chirp mass distribution of black hole binaries originated from massive binary star evolution requires additional model adjustments to reproduce the observed chirp mass distribution, Comment: 17 pages, 8 figures, one figure and reference added, revised version submitted to JCAP

Modern astrophysical methods of determination of spins of rotating stellar-mass black hole in close binaries and of supermassive black holes in active galactic nuclei are briefly discussed. Effective spins of coalescing binary black holes derived from LIGO/Virgo gravitational wave observations are specially addressed. We consider three types of coalescing binaries: double black holes, black hole-neutron star binaries and primordial double black holes. The effective spins of coalescing astrophysical binary black holes and black holes with neutron stars are calculated for two plausible models of black hole formations from stellar core collapses (without or with additional fallback from the stellar envelope) taking into account the stellar metallicity and star formation rate evolution in the Universe. The calculated distributions do not contradict the reported LIGO/Virgo observations. The effective spins of primordial coalescing stellar-mass black holes can reach a few per cent due to accretion spin-up in the cold external medium., Comment: 16 pages, 5 figures, submitted to Physics-Uspekhi