BHI conference Room: 20 Garden Street, Cambridge (Lunch will be served at 1:00 pm)
Robert Penna, Columbia University
Title: Characters of sphere diffeomorphisms
Abstract: Diffeomorphism groups act as infinite-dimensional symmetry groups in fluid dynamics and general relativity. We consider the group of area-preserving diffeomorphisms of the two-sphere, SDiff(S^2), and compute characters of irreducible representations. Physically, the characters encode a wealth of information about the distribution of states and eigenvalues of quantum systems with SDiff(S^2)...
BHI Conference Room 20, 20 Garden Street, Cambridge (Lunch will be served at 1pm).
1:30pm to 2:30pm
Very little is known about how black holes at the centres of galaxies grow to become “super" massive. Sensitive X-ray observations have enabled studies of the closest regions to growing supermassive black holes (aka Active Galactic Nuclei - AGN), and have revealed the majority are obscured by gas. Unfortunately though, the most obscured AGN are typically too faint to be detected in wide-field X-ray surveys. This has led to estimates of the fraction of heavily obscured AGN relative to the total population varying drastically between ~20-70%, yet a determination of this... Read more about Constructing a Census of Growing Supermassive Black Holes - First Results from the NuLANDS Survey