Observed Gravitational-Wave Populations

Understand

Ground-based gravitational-wave detectors like the Advanced LIGO, Advanced Virgo, and KAGRA experiments now regularly witness gravitational waves from compact binary mergers: the relativistic collisions of neutron stars and/or stellar-mass black holes.

• With hundreds of such events observed to date, gravitational-wave observations are enabling increasingly precise surveys of the demographics of merging compact binaries, including the distributions of their masses, rotation rates, and positions throughout the Universe.
• This article will provide an overview of our observational knowledge of the compact binary population, as it stands today.
• I will discuss, in turn, observations of binary black holes, binary neutron stars, and neutron star-black hole mergers, describing what is currently known (or not yet known) about these different gravitational-wave sources.