Professor and Edmund J. and Louise W. Kahn Term Chair in the Natural Sciences
- Professor (2009-)
- Co-spokesperson, LSST Dark Energy Science Collaboration (2012-)
- Co-Director, Center for Particle-Cosmology, U Penn (2009-)
- Co-coordinator, DES Weak Lensing Working Group (2007-)
- Co-chair, LSST Weak Lensing Science Collaboration (2006-2013)
- Board member on DES project (2006-) and LSST project (2006-2010)
- Editor, Focus Issue on Gravitational Lensing, New Journal of Physics (2007)
Ph.D., MIT (1994)
A.B., Physics (High Honors), Princeton University (1989)
My research area is cosmology and gravitational lensing. I am interested in understanding how small fluctuations in the early universe grew to form the large-scale structure observed today. This process is tied to the nature of dark matter and dark energy. Gravitational lensing, the shearing and magnification of light we receive from distant galaxies, is a powerful probe of these cosmological puzzles. I work in weak lensing: the small, percent level distortions in the shapes of distant galaxies. With weak lensing, we can map the mass distribution of galaxy clusters and the large-scale structure of the universe.
The properties of galaxies and their connection to the ambient dark matter is probed by imaging surveys of galaxies. These massive surveys are transforming our understanding of the universe. I am actively involved in the Dark Energy Survey (DES) and in the planning of the Large Synoptic Survey Telescope (LSST) and the space mission Euclid.
Astro 11: Introduction to Astrophysics I
Astro 12: Introduction to Astrophysics II
Physics 503: General Relativity
Physics 533: Topics in Cosmology