Speaker
Description
Compact objects can form binary systems in the vicinity of a supermassive black hole (SMBH), resulting in a hierarchical triple system. The presence of the SMBH can leave a detectable imprint on the gravitational waves emitted by the binary, which may be observed by next-generation gravitational wave detectors. One such imprint arises from resonances induced in the binary’s evolution by the presence of the SMBH. Among these, we focus on precession resonances, which occur when the periastron precession frequency of the binary becomes commensurate with the orbital frequencies governing the binary's motion around the SMBH.
We model the binary system up to 0.5 post-Newtonian (PN) order, while the SMBH is treated using the fully relativistic Schwarzschild metric. This framework allows us to include magnetic tidal moments in the coupling between the binary and the SMBH, which are purely relativistic and have no Newtonian analogue. These magnetic moments introduce a distinct relativistic signature of the SMBH in the binary's dynamics.
We demonstrate that relativistic effects and magnetic tidal moments give rise to a new resonance condition for precession resonances, specifically in the case of a quasi-circular orbit around the SMBH. This leads to multiple eccentricity kicks in the orbit of the compact binary over time, features that can be detectable by LISA, and results in an accelerated merger of the two compact objects. To the best of our knowledge, this represents the first observable effect of magnetic tidal moments in resonances within triple systems.
