Physics Colloquium

Ryan Keisler, Hubble Fellow, University of Chicago

Visiting Scholar, UT Austin, Texas Cosmology Center

"Cosmology with the South Pole Telescope"

4:15pm, RLM 4.102

Abstract:

I will describe a program of cosmological research centered on using measurements of the cosmic microwave background (CMB) to address questions relevant to physics: What is the absolute mass scale of neutrinos? How many species of neutrino-like particles were present in the early Universe? Did inflation occur, and, if so, at what energy scale?

A new generation of CMB experiments is targeting these questions, and I will focus on recent results from the South Pole Telescope (SPT).

The SPT is a ground-based mm-wave observatory located at the geographic south pole in Antarctica, and in 2011 finished its initial, 2500 square-degree survey.

The data from this survey provided an unprecedented combination of resolution, area, and sensitivity, and has been used to make ground-breaking measurements of the CMB anisotropy and the gravitational lensing of the CMB.

These measurements have, in conjunction with data from the WMAP satellite, led to strong constraints on models of inflation and on the the number of neutrino-like particle species present in the early universe.

In 2012, a new polarization-sensitive camera, SPT-POL, was installed on the SPT, and I will summarize its performance and prospects for detecting the "B-mode" CMB polarization pattern.

Finally, I will touch on what will be possible with a third-generation camera, SPT-3G. The leap in sensitivity provided by this camera will yield, for example, a constraint on the sum of the neutrino masses relevant for exploring the neutrino mass hierarchy.