Australia Telescope National Facility

Antony Stark Colloquium: Cosmology from the SPT

Abstract

The South Pole Telescope (SPT) is designed for the observation of low surface brightness phenomena at millimeter and submillimeter wavelengths, in particular features in the Cosmic Microwave Background (CMB). The 10 meter primary mirror is an off-axis, Gregorian design which gives a wide diffraction-limited field of view, low scattering, and high efficiency with no blockage of the primary aperture. Amundsen-Scott South Pole Station has been developed as an observatory site over the past three decades. The SPT became operational there in 2007. SPT survey data at 90, 160 and 220 GHz (with polarization) over the best 6% of the sky have substantially higher resolution and S/N than even the Planck satellite. Results so far include the first detection of more than 500 previously-unknown clusters of galaxies by the Sunyaev-Zel'dovich (SZ) effect, discovery of a class of lensed high-redshift submillimeter-wave galaxies, measurement of arcminute-scale features of the CMB, detection of the secondary-CMB and millimeter-wave bispectrum, detection of the kinetic SZ effect, detection and characterization of gravitational lensing of the CMB, constraints on the duration and timing of reionization, measurement of E-mode CMB polarization and its correlation with temperature, first detection of B-mode CMB polarization via cross-correlation with the IR background, new constraints on cosmological parameters and the properties of neutrino species. A third-generation detector array, SPT3G, is under development that has 16,000 background-limited bolometers that will yield an order-of-magnitude improvement in sensitivity. Future observations will discover thousands of galaxy clusters and groups, thereby measuring the history of dark energy and distinguishing between "normal" and "inverted" neutrino hierarchies. Measurement of B-mode polarization will yield a measurement of the tensor-scaler ratio and arcminute-scale mass maps of the CMB lensing potential.