Measuring the temperature anisotropy and gravitational lensing of the cosmic microwave background with the South Pole Telescope.

摘要

Over the past two decades, measurements of the cosmic microwave background (CMB) have provided profound insight into the nature of the universe. Detailed information about the composition and evolution of the universe is encoded in the temperature and polarization anisotropy of the CMB, the measurements of which have enabled powerful tests of cosmo- logical theory. In this thesis we present two studies of the CMB using data from the South Pole Telescope (SPT).;We first present a measurement of the temperature power spectrum of CMB from the 2500 square degree SPT-SZ survey using data from the first camera mounted on the SPT. This measurement and the cosmological interpretation was published in a pair of papers. Relative to all previous experiments at the time of publication, this analysis improved the precision of the power spectrum measurement over the entire range of angular multipoles reported (650 < ℓ < 3000). In combination with large angular scale measurements from WMAP7, these data provided several important constraints: the most significant detection of gravitational lensing of the CMB at the time (8.1sigma), the first > 5sigma detection of dark energy from CMB data alone, the first > 5sigma detection of a scalar spectra index below unity (in combination with external data sets), the tightest constraints on tensor modes at the time (r < 0.11 at 95% C.L., in combination with external data sets), and interesting constraints on neutrino physics and other extensions to the LCDM cosmological model.;Second, we measure the CMB gravitational lensing potential and its power spectrum using data from the polarization-sensitive camera SPTpol, the second camera installed on SPT. We use a quadratic estimator technique, which takes advantage of the statistical anisotropy induced by lensing in the CMB temperature and polarization fields to reconstruct the lensing potential. We measure the power spectrum of the lensing potential, and find that it is well fit by a fiducial LambdaCDM model. This measurement rejects the no-lensing hypothesis at 14sigma. Restricting ourselves to polarization data only, we reject the no-lensing hypothesis at 5.9sigma. This is the highest signal-to-noise map of the CMB lensing potential to date. The quadratic estimator analysis developed here sets the path for future analyses from SPTpol and the third generation experiment SPT-3G.