Speaker: Francisco Duque (CENTRA, IST)
Title: Gravitational tuning forks and hierarchical triple systems
Abstract: The LIGO-Virgo collaboration recently reported evidence for coalescences involving hierarchical triples composed by a stellar-mass binary system in the vicinity of a supermassive black hole (SMBH). We study gravitational wave emission in the strong-field regime of these systems and find that the binary system can resonantly excite the quasinormal modes of the SMBH, as in the resonant excitation of two tuning forks with matching frequencies. Moreover, the flux of energy crossing the SMBH horizon can be much more significant than in the standard extreme-mass-ratio inspirals. Consequently, these systems have a natural mechanism to probe strong-field physics. This can lead to distinctive signatures in their waveform such as Doppler shifts, aberration, lensing and strong amplitude modulations Finally, we address the impact of our results for the space-based LISA mission, which is particularly designed to detect gravitiational waves originated in galactic centers, where hierarchical triple systems are known to be abundant.
Room: ZOOM videoconference (contact justin.feng@tecnico.ulisboa.pt for URL)