Colloquium (Hankla Lecture)- Kate Grier

Kate Grier, University of Wisconsin- Madison

The Monsters of the Universe: Exploring Supermassive Black Holes and Quasars with the Sloan Digital Sky Survey

Abstract: Supermassive black holes are some of the most extreme and fascinating objects in ourUniverse. Their growth is intertwined with the lives of the galaxies in which they live, yet their formation and the means by which they interact with their galaxies remain open questions in astrophysics. The Sloan Digital Sky Survey (SDSS) has been monitoring  thousands of quasars — actively accreting supermassive black holes — over more than decade to explore the inner regions of these behemoths and measure their masses. We have collected hundreds of spectra each for thousands of quasars as a part of this ongoing effort, which began in 2014 and continues to date. While the main goal of this program is to measure supermassive black hole masses using the technique of reverberation mapping, these spectra have also allowed us to explore quasar variability and learn about supermassive black holes from numerous different angles, ranging from studies of broad absorption-line variability and quasar outflows, to studies of extreme variability events and changing-look quasars. I will give an overview of the SDSS reverberation mapping program, from SDSS-IV through the up-and-coming After-Sloan 5 program, and highlight some of the work that we have been doing that has been enabled by this unprecedented spectral dataset.

Bio: Kate Grier is an assistant professor at the University of Wisconsin-Madison Department of Astronomy. She grew up in the Chicago area and received her undergraduate degrees in Physics and Astronomy at the University of Illinois at Urbana-Champaign, followed by a Ph.D in astronomy from the Ohio State University. She then served as the Planetarium Director at OSU for a year, and moved on as a Postdoctoral Research Fellow at Penn State University and then the University of Arizona. Kate started as an assistant professor at UW-Madison in Fall 2022. Her research focuses primarily on learning about supermassive black holes through observations of the variability of quasars. She is the Program Head for the Dynamic Universe Explorer program, which is a part of the upcoming After-Sloan 5program that will follow the Sloan Digital Sky Survey V, and has been an active and leading member of SDSS reverberation mapping efforts over the past decade.

Wednesday, September 23, 2026 @ The Commons at 4:00 P.M. Room 235/ 237 ( non-standard time)

Host: Jessie Runnoe