- 2006- Reese W. Flower Professor of Astronomy and Astrophysics, University of Pennsylvania
- 2003-2006 Class of 1965 Term Chair, University of Pennsylvania
- 2000-2003 Associate Professor, University of Pennsylvania
- 1996-2000 Assistant Professor, University of Pennsylvania
- 1995-1996 Research Associate, Princeton University
- 1994-1995 Postdoctoral Researcher, Princeton University
- 1993-1994 Postdoctoral Researcher, University of California at Berkeley
M.S., Ph.D, University of California at Berkeley (1993)
B.A., University of Wisconsin – Madison (1988)
My research focuses on experimental cosmology at millimeter and submillimeter wavelengths. Cosmology is the study how the Universe came into being and how it evolved into what we see today. Unlike a traditional astronomer who might study an individual star or galaxy to determine its properties, I collect data from which I make statistical inferences about the evolutionary history of the Universe. The evolutionary history can then tell us about the physical parameters which govern the way our universe behaves. To this end, I design and build sophisticated instrumentation and telescopes which I use to observe from high-altitude balloons and the high-plateaus of Chile.
Projects:
- The Simons Observatory (SO) is a major initiative funded by the Simons Foundation and the National Science Foundation. We are deploying state-of-the-art telescopes and cameras at our site on Cerro Toco in Northern Chile. I was the inaugural Spokesperson (2016-2018) and am currently the Co-Director of the Observatory. My laboratory at Penn leads the development of the Large Aperture Telescope (LAT) and the Large Aperture Telescope Receiver (LATR). For more information see: https://simonsobservatory.org/
- The Atacama Cosmology Telescope (ACT) was decommissioned in 2023 and is currently completing the analysis of the last data set, DR6. In its 15 years of observations, the 6 meter diameter ACT telescope located on Cerro Toco in Northern Chile produced exciting cosmological and astrophysical results. I am currently the Deputy Director of ACT. For more information see: https://act.princeton.edu/
- The MUSTANG-2 is a 3 millimeter receiver developed at Penn using microwave-MUX readout of transition edge sensor (TES) detectors developed at NIST. We operate MUSTANG-2 on the Green Bank Telescope (GBT) in West Virginia. Utilizing the 100 meter dish we obtain 9 arcsecond resolution images of the Sunyaev-Zel'dovic effect in galaxy clusters as well as other high resolution measurements of the millimeter sky. See http://www.gb.nrao.edu/mustang/
- The Balloon-borne Large Aperture Telescope (BLAST) was a long running NASA high altitude balloon program. We studied star formation in high-redshift galaxies as well as star formation in the Milky Way and the effect of polarized dust as a foreground for current and future CMB experiments. I led BLAST for the last 17 years and it had its last flight in 2020. A new version of BLAST is being proposed by my former student, Nick Galitzki who is now at UT Austin.
Astro 001: Survey of the Universe
Physics 150: Principles I
Physics 101: General Physics