An effective-one-body gravitational waveform model for large-mass-ratio inspiralling black hole binaries

The effective-one-body (EOB) approach is a powerful formalism that maps the two-body problem in general relativity into the motion of a single body in an effective metric. This provides a general framework that allows to exploit results from many other approaches, as post-Newtonian computations, numerical relativity, and gravitational self-force theory. EOB-based gravitational waveform models are nowadays providing fast and accurate templates for coalescences of comparable-mass compact binaries, that constitute the only type of event observed by the currently operating detectors. The next generation of detectors will instead allow us to receive the gravitational signal of a wider collection of sources, among which are large-mass-ratio inspirals. These are systems made up of a stellar-mass compact object orbiting around a massive or super massive black hole, and require a more accurate modelling. After briefly introducing the EOB formalism, I will discuss ongoing efforts in adapting an EOB waveform model in order to efficiently describe the evolution of large-mass-ratio binaries.