Lecturer: Julian Krolik, John Hopkins University
Abstract:
Today's galaxies are thought to be built from successive mergers of smaller galaxies, while
observations of present-day galaxies show that there is a supermassive (10^6 -- 10^9 solar mass) black hole at the center of essentially every good-sized galaxy. Galaxy mergers are therefore very likely to bring two supermassive black holes into the merged system, where gravitational interactions with stars should bring them relatively quickly into its center and they can form a bound pair. Given the right environment, this pair may merge, emitting gravitational waves that could be seen by a future space-based gravitational wave observatory. But can we find supermassive black hole binaries now, long before such a spacecraft launches, using photons?
In this talk, I will review the physics of how such a system evolves, producing light distinctive in both spectrum and time-dependence and illustrating a number of dynamical processes unique to relativistic binaries.