Inspiral, transition and plunge: a framework for complete waveforms in the small-mass-ratio expansion

The project concerns the waveform modelling of the slow inspiral and coalescence of stellar or intermediate mass black holes into intermediate and supermassive black holes, known as IMRACs and EMRIs. EMRIs are prime sources for LISA as they lie entirely in the LISA frequency band of observation. Their orbits are generic and highly relativistic, displaying extreme forms of periastron and orbital plane precession, and executing 10^3 – 10^5 orbital cycles. The observation of EMRIs by LISA therefore can yield precise tests of General Relativity, since the gravitational wave signal encodes information on the spacetime of the central massive object. We plan on improving the waveform models to the level of accuracy that is needed to be able to translate strain variations detected by LISA to physical properties of these gravitational wave sources.