The transition from inspiral to plunge marks the breakdown of the slow-evolution approximation that underpins adiabatic and post-adiabatic waveform modelling. As the small body approaches the innermost stable orbit, dissipative and conservative effects can no longer be cleanly separated by timescale, and a dedicated matched-asymptotic treatment is required. Beyond the plunge, the remnant black hole rings down through a superposition of quasinormal modes whose amplitudes are determined by the dynamics of the final orbits.
We develop matched-asymptotic descriptions of the transition-to-plunge regime, attach first-principles ringdown models, and study how quasinormal mode amplitudes — including higher-order overtones — depend on the inspiral history. Together these advances close the gap between the carefully modelled inspiral signal and the final ringdown.
Current focus:
- Transition-to-plunge expansion at second post-adiabatic order
- Predicting ringdown amplitudes from inspiral dynamics
- Quasinormal mode overtone content in EMRI ringdowns
- Stitching late inspiral, plunge, and ringdown into continuous waveforms