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Research @ PFC
Research Highlights, 2012
The South Pole Telescope Measures Small-scale Structure of the Cosmic Microwave Background to Unprecedented Precision
April 23, 2012 | Read more
In a paper published in December in the Astrophysical Journal (R. Keisler et al., 2011 ApJ 743 28), the SPT team used approximately one third of the total 2500-square-degree survey data in just one of the three colors to make the most precise measurement yet of the region of the CMB angular power spectrum known as the damping tail. The CMB power spectrum (which measures fluctuations in CMB temperature as a function of angular scale) is predicted to have a characteristic series of peaks, caused by oscillations in the tightly coupled plasma of charged particles and photons in the early universe.
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A slightly surprising result from the SPT measurement is that there appears to be stronger damping than the simple 'concordance' cosmological model would predict. This excess damping could be explained by a higher fraction of primordial helium than is indicated by local measurements, a non-standard number of relativistic particle species in the early universe, or a non-standard shape of the primordial power spectrum. If any of these scenarios is borne out, it would have profound implications for fields of physics well beyond CMB studies and cosmology.
The SPT team is currently working on a measurement of the CMB power spectrum from the full 2500-square-degree survey, and the team recently installed a new, even more sensitive camera on the telescope (one capable of measuring not just the intensity of the CMB radiation but also its polarization properties). Results from the SPT in the near future will further exploit the promise of cosmological observations to directly constraining fundamental physics.
The SPT is a collaboration among scientists at several institutions including the University of Chicago / KICP, Argonne National Laboratory, Cardiff University, Case Western Reserve University, Harvard University, Ludwig-Maximilians-Universit, Smithsonian Astrophysical Observatory, McGill University, University of California at Berkeley, University of California at Davis, University of Colorado at Boulder and the University of Michigan.
The SPT is funded primarily by the NSF Office of Polar Programs. Partial support is also provided by the NSF-funded Physics Frontier Center of the Kavli Institute for Cosmological Physics, the Kavli Foundation and the Gordon and Betty Moore Foundation.
KICP members participating in the South Pole Telescope collaboration include KICP faculty John Carlstrom (PI), Mike Gladders, Wayne Hu, Andrey Kravtsov, and Steve Meyer; senior researchers Clarence Chang, Tom Crawford, Erik Leitch, and Kathryn Schaffer; postdocs Brad Benson, F. William High, Steven Hoover, Ryan Keisler, Jared Mehl, and Tom Plagge; and graduate students Lindsey Bleem, Abby Crites, Monica Mocanu, Tyler Natoli, and Kyle Story.