Radiation sources beyond the vacuum 2-body problem

Gravitational wave astronomy revolutionized physics. My PhD focuses on the study of systems of radiation sources around massive black holes. In the first project of my PhD, we investigated the motion of a radiating charged particle around a spinning black hole in the presence of a magnetic field. These systems are important from the point of view of energy extraction mechanisms from black holes, a proposed source of high-energy cosmic rays.

Our work corrected misconceptions in the literature about the dynamics of such systems and showed that one can use superradiance to extract energy from the black hole, outspiralling and drifting away from the black hole.
The second, and current, project is focused on the understanding of the gravitational-wave signal produced when a stellar-mass binary orbits a spinning massive black hole.

We use Dixon’s formalism to describe the stellar binary as a pointlike particle with a time-varying quadrupole moment. Using the Teukolsky formalism, we calculate the resulting gravitational radiation, produced by both the internal motion of the stellar binary components around the center of mass, and by the motion of the latter around the massive black hole.

The waveform obtained, from first principles, shows rich physics, namely signatures of Doppler modulation, relativistic beaming, strong lensing, quasi-normal mode excitation, and helicity-dependent scattering. The science potential of these systems can’t be overstated, and it might be unlocked with future, more sensitive detectors like LISA. However, this requires challenging work to be done on the waveform modeling side; my PhD aims to be a stepping stone in this direction.