Waveform Modelling for Gravitational Wave Astrophysics

Accurate models of the gravitational-wave signal emitted by generic configurations of black-hole binaries as they inspiral and collide, have been essential to measure the properties of the black holes observed in the first gravitational-wave detections from Advanced LIGO. One of the most pressing problems is the modelling of generic binaries, where the black-hole spins introduce wild dynamics that generate complicated waveforms. We currently have a preliminary waveform model, but this does not take into account the subtle precession effects at the black holes approach merger, or their effect on the waveform as the final black hole rings down. It is also important, for both gravitational-wave searches and measurements of physical parameters, to determine those physical parameters that have the dominant effects on the waveform structure, and are therefore the parameters that can be most precisely measured. This has an impact both on how we construct waveform models, and on the astrophysical questions that can be answered with gravitational-wave observations. Several research directions are possible, including modelling the late-inspiral waveforms of generic systems, using these models to estimate the physics that can be measured from GW observations, and studying astrophysics from binary-black-hole observations.