20th Seminar (Part 2)
Recently, intense attention has focused on the possibility that merging supermassive black hole binaries could be observed with both electromagnetic and gravitational waves. Such multi-messenger studies would (i) probe dark energy out to z~10, and (ii) allow follow-up studies of active galactic nuclei with central engines whose masses and spins are independently known through gravitational waves. I will present semianalytic, time-dependent models of the electromagnetic signature of a thin accretion disk around a coalescing supermassive black hole binary. I will discuss several scenarios for observing such a signature.