Abstract

Scalar, electromagnetic and linear gravitational radiation do not solely propagate on the null cone in 3+1 dimensions in curved spacetimes, contrary to their well-known behavior in flat spacetime. Their additional propagation inside the null cone is known as the tail effect. In the first part of the talk, I will present new results for the tail-induced electromagnetic and gravitational self-force for a test particle in orbit around a central body. This test particle will produce a signal whose tail will interact with its future worldline, thus producing a tail-induced self-force. I will show that the self force can serve as a probe of the internal structure of the central object, with possible future implications for neutron star-black hole mergers. During the second part of the talk, I will present new results on the propagation of the ” tail radiation” resulting from inhomogeneities in curved spacetime. If observable, tail radiation has the potential to become a new window in the universe and my interest is its application on astrophysical systems, hence offering complementary information beyond the usual lensing studies in GR.