Speaker:  Dr. Jonathan Zrake

Host:  Prof. Tamara Bogdanovic

Title: Variability of binary AGNs 

Abstract:

I will discuss recent results from numerical modeling of the electromagnetic (EM) variability signatures of accreting supermassive black hole (SMBH) binaries. Orbiting SMBH binaries produce both periodic, and stochastic, variability with potentially tell-tale signatures, especially in the shape of the power spectral distribution (PSD) of the optical continuum emission. Furthermore, the gravitational wave (GW) driven inspiral and merger of the two black holes can induce either of two types of “changing look” AGN events — Type-A events in which the AGN light is dimmest at the time of the merger, and Type-B events in which the AGN light is brightest around the merger time. The two types correspond to the direction of angular momentum flow between the binary orbit and the surrounding gas disk, and produce a correlated phase drifting in the LISA band, creating a new avenue for multi-messenger (EM+GW) study of binary black holes with e.g. LSST and LISA.