Testing the nature of dark compact objects through the excitation of resonances during inspiral.
Presenting author: Adrian del Rio Vega
A remarkable prediction of General Relativity is the existence of black holes, whose validity requires strong observational evidence. Dark compact, horizonless objects are also predicted to arise at a phenomenological level in different scenarios, and several mechanisms have been proposed to test the black hole nature of compact objects in astrophysics based on gravitational wave observations. In this talk, we study the possibility of excitation of the proper modes of oscillation of a massive object that could take place when the orbital frequency of a particle orbiting around approaches a characteristic frequency of the system (a quasi-normal mode), and on the possibility that such excitations show up in the detected GW signal. Such excitations of characteristic modes do not take place if the central object is a black hole since its modes are excited at the “light ring” (for which timelike orbits are unstable), making a priori mode excitation by inspiral bodies a useful tool in distinguishing black holes from dark compact objects. Our results indicate that resonances are indeed excited for very compact horizonless bodies. However we find that their impact on the phase of the GW signal is negligible, given that resonances are crossed very quickly during inspiral.
Oral presentation: yes. Poster: no.