School of Physics Colloquium

Title: It's Raining Black Holes, Hallelujah!

Abstract: Gravitational wave (GW) emissions from extreme-mass-ratio inspirals (EMRIs) are promising sources for low-frequency GW detectors. EMRIs result from a supermassive black hole (SMBH) that captures a stellar-mass compact object, such as BH. Two-body relaxation has been proposed as one of the likely physical processes to form EMRIs efficiently. In this process, weak two-body kicks from the population of stars and compact objects surrounding the SMBH can change the BH's orbit over time, driving it into the SMBH. On the other hand, perturbations from SMBH companions via the eccentric Kozai-Lidov (EKL) mechanism can excite the SMBH to high eccentricities, thereby forming EMRIs. In this talk, I will demonstrate that combining these two processes is essential to comprehending the dynamics of EMRIs progenitors. I will also show that EMRIs are naturally formed in SMBH binaries with higher efficiency than either of these processes considered alone. Finally, I'll show how this mechanism can yield raining stars (in the form of tidal disruption events); hallelujah!

Bio: Smadar Naoz is a theoretical astrophysicist who works on a wide range of topics, from forming the very first stars in the Universe to the dynamics of planets, stars, and black holes. She did her undergraduate and master's degrees at the Hebrew University of Jerusalem and her Ph.D. at Tel-Aviv University. She was then a CIERA and an IAU Gruber postdoc fellow at Northwestern University and then an ITC and an Einstein fellow at Harvard University. She joined the UCLA faculty in 2014.