Seminars
Seminars occur on Wednesdays from 12:00-1:00 PM Pacific in ISB 130 with a hybrid option over Zoom unless otherwise posted. To join the mailing list, please contact Prof. Christopher Smallwood at christopher.smallwood@sjsu.edu with the words "Seminars and Events" included in the subject heading.
This Week
Constraining Black Hole Spin through Electromagnetic Observations
Delilah Gates, Harvard University
Wednesady, 11/19/2025, 12:00-1:15pm Pacific
Abstract: Black holes are a remarkable prediction of Einstein’s theory of General Relativity.
Astrophysical black holes, which present the strongest gravitational environments
in nature, are surprisingly simple objects described only by their mass and their
rate of rotation (i.e., spin). Observing black holes in the stationary regime is difficult
because they do not emit or reflect light. Nonetheless, we can study these strong-gravity
environments by leveraging the extreme relativistic effects that black holes impose
on light emitted from nearby sources. In this talk, I discuss how spectra and horizon-scale
images can be used to constrain black hole spin using two relativistic effects: frequency
shifting and strong lensing.
Bio: Dr. Delilah Gates received her Ph.D. in Physics from Harvard University in 2021 and B.S.s in Physics and in Mathematics from the University of Maryland, College Park in 2015. Before returning to Harvard, Delilah was a postdoctoral fellow of the Princeton Gravity Initiative and the Princeton Future Faculty in the Physical Sciences. Delilah’s research focuses on constraining properties of black holes and their astrophysical environments through analytic and semi-analytic methods which leverage features of black hole spacetime geometries and the radiation sourced near black holes.
