Daniel Kapec

Harvard CMSA, December 8, 1:00 pm

The Black Hole Photon Ring, Old and New

The black hole photon ring is a prime target for upcoming space-based VLBI missions seeking to image the fine structure of astrophysical black holes. The photon ring controls a surprising number of observational signatures relevant to both current and future gravitational experiments. Its intricate, nested subring structure predicts distinct interferometric signatures in black hole images, and the ring also controls an interesting sector of the black hole’s quasinormal mode spectrum. Semiclassical analysis also suggests an important role for the photon ring in the (still mysterious) quantum mechanical description of the Kerr black hole. If time permits, I will also discuss a number of recently discovered emergent symmetries related to the intricate self-similar structure of the photon ring.