South Pole Telescope (SPT)

The South Pole Telescope (SPT) is a 10-meter telescope at the Amundsen-Scott South Pole research station in Antarctica. Taking advantage of the exceptionally clear, dry, and stable atmosphere at the South Pole, the SPT has been used to map large areas of the sky with high sensitivity at millimeter wavelengths.

Among the initial science goals of the SPT was to explore the nature of dark energy, an unexplained phenomenon responsible for the observed acceleration in the expansion of the universe. The SPT team searches for massive clusters of galaxies by looking for spectral distortions in the cosmic microwave background (CMB) known as the Sunyaev-Zel’dovich or SZ effect. Dark energy inhibits the growth of galaxy clusters, so studying the population of clusters through cosmic time helped constrain models of dark energy.

Following the initial SPT survey, the polarization sensitive SPTpol detector was installed and SPT began a program of searching for B-mode polarization in the CMB. This survey resulted in the first detection of B-mode polarization in the CMB. During the 2016-17 austral summer, the SPT-3G camera was installed on the telescope, significantly increasing sensitivity to B modes and a host of other signals in the microwave sky.