Physics Colloquium: Caustic Echoes from Black HolesDate(s): 11/14/2012 2:00 PM - 11/14/20123:00 PM
Location: Seng 102
Contact: Robert Fisher firstname.lastname@example.org 508-999-8353
Speaker: Anil Zenginoğlu, Caltech Title: Caustic echoes from black holes Abstract: We encounter caustics wherever light is focussed: in a swimming pool due to refraction, or in a coffee mug due to reflection. Caustics also occur around black holes due to focussing by spacetime curvature. It has recently been found that a flash of light near a black hole echoes in a specific pattern through caustics. Such echoes play an essential role in the computation of self-force acting on a compact object moving into a supermassive black hole. Understanding this phenomenon is important for the prediction of gravitational waves to be detected by future, space-based interferometers. I will present the first numerical simulations of caustic echoes from black holes. Their computation requires efficient handling of multiple scales, in particular the scale of the ideal observer infinitely far away. I will describe a novel solution to this problem, called hyperboloidal compactification, that allows us to compute solutions of wave equations on infinite domains. I will also explain the relationship between caustic echoes and the spiralling of a small black hole into a supermassive one.