CCA Colloquium: Itai Linial

Title: Dynamics and Energetic Transients in Galactic Nuclei

Abstract: Centers of galaxies host a variety of dynamical processes, owing to the high density of stars and the presence of a central Supermassive Black Hole (SMBH). Orbital relaxation brings stellar objects into close encounters with the SMBH, driving a variety of energetic phenomena. These include tidal disruption events, stellar collisions, the formation of X-ray binaries, compact object mergers detectable by LIGO, and gravitational wave (GW) inspirals into the SMBH. In this talk, I will explore the mechanisms behind these processes and their observable signatures, with an emphasis on newly discovered classes of repeating flares associated with SMBHs. I will discuss theoretical models, key open questions, and how these phenomena inform our understanding of accretion physics, SMBH growth and evolution, and the connection to their host galaxies. A powerful array of current and upcoming time-domain surveys and instruments (including Rubin/LSST, Roman, ULTRASAT, UVEX, SKA, AXIS, as well as next-generation GW detectors, and LISA) will uncover thousands of high-energy sources in galactic nuclei. I will highlight how theoretical interpretation of these discoveries can address fundamental questions in astrophysics, and conclude with broader implications for multi-messenger observations in the era of space-based GW detectors.