Peter Schor, MIT
Title: Scrambling Time and Causal Structure of the Photon Sphere of a Schwarzschild Black Hole
Abstract: The fast scrambling conjecture says that black holes are the fastest scramblers of information, and that they scramble it in time order M Log M, where M is the mass of the black hole in natural units. We point out that the scrambling time depends on the exact definition of scrambling and give an argument that for the stronger definitions of scrambling, the scrambling time cannot be this small unless there is non-standard physics taking place in some realm where we naively would not expect it.
Dom Pesce, SAO
Title: AGN accretion disk megamasers
Abstract: Water vapor masers emitting at a frequency of 22 GHz are often associated with AGN, where they are called "megamasers" because of their large luminosities. VLBI observations of these megamasers reveal that they reside in a thin, edge-on accretion disk orbiting the supermassive black hole (SMBH) at sub-parsec radii. By leveraging the unique geometry and simple dynamics of disk megamaser systems, we obtain powerful astrophysical tools for studying AGN, SMBHs, and cosmology. In this talk I'll cover (1) some recent work by the Megamaser Cosmology Project, (2) an offshoot project to identify SMBHs exhibiting peculiar motion, and (3) new prospects in the field of (sub)millimeter water megamaser research.