Journées Scientifiques de l'Action Thématique GRAM

Session

Gravitation

26 nov. 2026, 16:00

Amphi Pierre-Gilles de Gennes (Université Paris Cité)

1. Detectability of the spin parameters of SgrA* using multiple S stars

Karim Abd El Dayem (Observatoire de Paris (LESIA))

26/11/2026 16:00

The orbits of S stars around the Galactic Center black hole, Sgr~A*, offer a unique opportunity to probe the relativistic regime of gravity and test the no-hair theorem. While the Schwarzschild precession has been detected with S2, the detection of spin-induced (Kerr) effects—Lense–Thirring and quadrupole moment terms—remains a major observational challenge. We aim to quantify the time needed...

20. Probing gravitational waves using the orbital dynamics of binary systems

26/11/2026 16:30

The internal dynamics of a binary system can be affected by the passage of gravitational waves (GWs). This effect is significantly enhanced when the GW frequency is in resonance with the orbital frequency of the binary system. Recently, this phenomenon has been proposed as a novel approach to detecting GWs in the largely unexplored microhertz frequency band, using precise measurements of the...