Angela Q. Lewis
Research on cosmology takes place in a number of places in the Princeton community: Physics, the Department of Astrophysical Sciences, and The Institute for Advanced Study. Theory, data analysis, and instrumentation are all vigorously pursued in an interactive and vibrant community. The experimental and observational cosmology group in the Physics Department is involved in measurements of the cosmic microwave background (CMB), surveys of large scale cosmic structure, and observations of galactic clusters. The CMB is the after glow of the hot early stages of the expansion of our universe. In the angular distribution of its temperature and polarization is encoded the history of the evolution of the universe and the values of the cosmological parameters. Measurements have reached the stage where we now have a "standard model of cosmology" and we are exploring the details of the model. These are exciting times. Efforts are underway to find gravitational radiation from the Big Bang, to determine the sum of the neutrino masses, to search for new particle species, to map out the earliest cosmic structures, and to find the parameters of the fields that produced the Big Bang. Through comparisons with optical surveys we measure how the universe evolved and test theories of gravity. With a new balloon-borne optical telescope, we will measure the masses of dozens of galaxy clusters through their gravitational lensing effect.
Princeton is the lead partner on the ACT and SPIDER, projects currently, the U.S. lead on SUPERBIT, and closely involved with PLANCK and the Simons Observatory. Recently concluded projects include QUIET, TRUCE, and WMAP. The WMAP mission was a partnership between the NASA Goddard Space Flight Center and Princeton University. The "W" is for Wilkinson; David Wilkinson was a faculty member in the department from 1965 until his death in 2002 and launched the group on its long mission of measuring the temperature and polarization of the CMB. Ph.D. theses generally involve building sensitive receivers and instruments, observing the cosmos from the ground, balloons, or satellites, analyzing data from those observations, or some combinations of these. Interactions and collaborations are abundant.
ACT's first array of polarized bolometers
Pictured from left to right. Emily Grace (graduate student), Suzanne Staggs (professor), Laura Newburgh (postdoc), Christine Pappas (graduate student), Sara Simon (graduate student) who also contributed is not shown.