Processes of Stellar Destruction in Galactic Nuclei and Quasi-Periodic X-Ray Eruptions
Centers of galaxies are fertile environments for a variety of dynamical processes, owing to the high density of stars and the presence of a central supermassive black hole. Stars may occasionally be deflected onto a deadly trajectory, passing too close to the central black hole where they are being tidally disrupted, or they may gently inspiral towards the black hole due to the emission of gravitational waves, until they fill their Roche lobe and shed mass towards the supermassive black hole, forming a “stellar extreme mass-ratio inspiral (EMRI)”. I will review these processes and discuss a possible connection between stellar EMRIs and a recently discovered class of transient X-ray events, known as Quasi-Periodic Eruptions (QPEs) associated with galactic nuclei. I will conclude by discussing the predictions of our model and the association between QPEs and other nuclear transients, and comment on their prospects as multi-messenger targets in the era of space-based GW detectors, and all-sky X-ray surveys.