Résumé / Abstract Seminaire_GReCO

"Tuning forks and galactic centers"

Francisco Duque
Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico (Lisbonne, Portugal)

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 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. We also conclude that the accretion of bright spots, whether in optical or gravitational waves, follows a global exponential decay controlled by the light-ring. Finally, we address the impact of our results to the future of gravitational wave interferometry and black hole imaging.

lundi 15 mars 2021 - 11:00
Institut d'Astrophysique de Paris

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