Gravitational wave astronomy: astrophysical and cosmological inferences

TL;DR

This paper reviews key gravitational wave discoveries from LIGO-Virgo, explores astrophysical origins of observed signals, and discusses the potential of pulsar timing arrays to detect a stochastic gravitational-wave background.

Contribution

It presents an overview of recent gravitational wave detections, proposes a formation channel for binary black holes, and discusses the prospects of nano-Hz background detection.

Findings

Correlation between black hole spin and mass ratio explained by accretion

Detection of gravitational waves from binary black hole mergers

Searches for stochastic background in pulsar timing data

Abstract

We briefly discuss the most prominent results and specific sources detected by gravitational-wave observatories LIGO-Virgo during first three O1-O3 runs, as well as possible astrophysical and cosmological channels of their formation. We show that it is possible to explain the observed correlation between the effective spin of coalescing binary black holes and mass ratio of the components by accretion from the ambient medium onto primordial binary black holes. We also briefly discuss the recent results of searches for stochastic gravitational-wave background in the nano-Hz frequency band by pulsar timing arrays.