Research Interests

My research is primarily focused on observational cosmology. I have been very active in measuring the current expansion rate of the universe, or the Hubble constant, making use of large optical telescopes, both on the ground, as well as the Hubble Space Telescope. I was a co-principal investigator of the Hubble key project to measure the Hubble constant. This project centered on the discovery and use of Cepheid variable stars and their application to the extragalactic distance scale. Recently, my interests have turned toward using supernovae as probes of the past expansion rate of the universe. We have begun a new, long-term Carnegie supernova project with the goal of elucidating the nature of dark energy in the universe. I have also had a long-standing interest in the evolution of galaxies, particularly the study of the nearby universe and the stellar populations of galaxies.

Membership Type

Member

Election Year

2003

Primary Section

Section 12: Astronomy

Secondary Section

Section 13: Physics