The Catholic University of America

All Colloquia are held in Hannan 106 at 4:00. Refreshments served at 3:45.


Department of Physics



Dr. Lou Strolger

Space Telescope Science Institute


High Redshift Supernovae: Beyond The Epoch of Dark Energy


For nearly two decades the Hubble Space Telescope has been heavily used to locate supernovae in high redshift environments, with the primary goal of improving constraints on the nature of dark energy. Along the way we have made surprising observations on the nature of supernovae themselves, and clues to their elusive progenitor mechanisms, some of which are difficult to reconcile with observations at much lower redshift.  From complete volumetric supernova rate histories, that for the first time extend to z > 2, we find type Ia supernova delay-time distributions are consistent with a power law of index -1, but with the fraction of prompt (t_d < 500 Myr) much less than expected from various ground-based surveys. Core collapse supernova rates trace the cosmic star formation rate history, but require stellar progenitors more massive than has been seen in deep studies of nearby events (M > 20 M_sol). I will also detail our current campaigns on clusters of galaxies (RELICS and the Frontier Fields), where gravitational lens magnification provides a real potential for locating the first, primordial supernovae, while also providing useful constraints on the mass models of the foreground gravitational lenses.


Wednesday, October 26, 2016


108 Hannan Hall

Refreshments will be served at 3:45


Sponsored in part by the Graduate Student Association

For more information or if you would like to request disability accommodations, please contact:



Patrick Burke  (202) 319-5315