Hall, Patrick

Patrick Hall

Full Professor
Ph.D. (Arizona)
phall@yorku.ca

Department(s): Physics and Astronomy

Office: 337 Petrie Science & Engineering Building (PSE)
Phone: (416)736-2100 ext. 77752

Research Fields
Astronomy and Astrophysics

Graduate Program Appointment
Full Member: Eligible to supervise M.Sc. or Ph.D.

Research Types
Computational, Experimental, Theoretical


Research specialization
Active Galactic Nuclei, especially quasars; Black holes; Gravitational lensing.


When matter spirals into a supermassive black hole at the centre of a galaxy, a kind of friction can heat the matter up until it shines brightly enough to be seen all the way across the universe. We call such objects quasars. I am interested in understanding more clearly the dynamics of gas spiralling around black holes in quasars. That knowledge will improve our ability to infer the physical properties of quasars and their black holes (such as mass and spin) from the details of the light they produce. I am particularly interested in outflows of gas from quasars. Much of the mass spiralling around in a quasar ends up in the black hole, but some of it is flung outwards and is sometimes visible in the spectrum of the quasar. Establishing the connections between those absorption lines and the emission lines seen in most quasars will help us understand how quasars work and how galaxies form. I am also interested in gravitational lensing, which can take a small, faint galaxy and stretch it out into a long, luminous arc. My research is both experimental and theoretical. I do much of my experimental work using online databases from large astronomical surveys, supplementing data as necessary with modern instruments on large telescopes.