Cosmological Parameters from the QUAD CMB Polarization Experiment

• Published in: The Astrophysical journal Vol. 701; no. 2; pp. 857 - 864
• Main Authors: Castro, P. G, Ade, P, Bock, J, Bowden, M, Brown, M. L, Cahill, G, Church, S, Culverhouse, T, Friedman, R. B, Ganga, K, Gear, W. K, Gupta, S, Hinderks, J, Kovac, J, Lange, A. E, Leitch, E, Melhuish, S. J, Memari, Y, Murphy, J. A, Orlando, A, Pryke, C, Schwarz, R, O'Sullivan, C, Piccirillo, L, Rajguru, N, Rusholme, B, Taylor, A. N, Thompson, K. L, Turner, A. H, Wu, E. Y. S, Zemcov, M
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.08.2009; IOP; American Astronomical Society
• Subjects: Astronomy; Astrophysics; Cosmology and Extra-Galactic Astrophysics; Earth, ocean, space; Exact sciences and technology; Physics; Sciences of the Universe; Statistical method; Polarization; methods: statistical; Cosmological parameter; Cosmic background radiation; cosmic microwave background; Cosmology; cosmological parameters; polarization
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/701/2/857

In this paper, we present a parameter estimation analysis of the polarization and temperature power spectra from the second and third season of observations with the QUaD experiment. QUaD has for the first time detected multiple acoustic peaks in the E-mode polarization spectrum with high significance. Although QUaD-only parameter constraints are not competitive with previous results for the standard six-parameter Lambda CDM cosmology, they do allow meaningful polarization-only parameter analyses for the first time. In a standard six-parameter Lambda CDM analysis, we find the QUaD TT power spectrum to be in good agreement with previous results. However, the QUaD polarization data show some tension with Lambda CDM. The origin of this 1 sigma -2 sigma tension remains unclear, and may point to new physics, residual systematics, or simple random chance. We also combine QUaD with the five-year WMAP data set and the SDSS luminous red galaxies 4th data release power spectrum, and extend our analysis to constrain individual isocurvature mode fractions, constraining cold dark matter density, alpha cdmi < 0.11 (95% confidence limit (CL)), neutrino density, alpha ndi < 0.26 (95% CL), and neutrino velocity, alpha nvi < 0.23 (95% CL), modes. Our analysis sets a benchmark for future polarization experiments.