Gravity Seminars

Over the past years, electromagnetic and gravitational observations have been used to understand the nature of black holes and the material around them. Our ability to learn about the underlying physics, however, depends heavily on our understanding of the gravity theory that describes the geometry around these compact objects, and for the electromagnetic observations, also on the complex astrophysics that produces the observed radiation. In this talk, I will discuss our current ability to constrain and detect deviations from general relativity using (i) the electromagnetic radiation emitted by an accretion disk around a black hole, and (ii) the gravitational waves produced when comparable-mass black holes collide, and when a small compact object falls into a supermassive one in an extreme mass-ratio inspiral. I will also compare the constraining capabilities of these two types of observations to show how current gravitational wave observations have already placed constraints on possible modifications to general relativity, that are more stringent than what can be achieved with current and near-future electromagnetic observations.