Review: the landscape of gravitational wave astronomy

The direct detection of gravitational waves from a binary black hole merger has opened a new window in observational astronomy. The first three observing runs of the LIGO/Virgo groundbased interferometers have produced a broad range of scientific results, including the first observationsof a binary neutron star merger and a neutron star-black hole merger. The observations include some exceptional events and other mergers reported in the GWTC-1, GWTC-2, GWTC-2.1, GWTC-3 catalogues, that have allowed tests of general relativity and studies of black hole and neutron star populations. The paper is a concise review of ground-based gravitational wave astronomy and related multi-messenger observations over the electromagnetic spectrum and the neutrino domain. Since the spectrum of gravitational waves extends over a broad frequency range, other techniques for gravitational wave detection outside the sensitivity band of ground-based interferometers will also be discussed.