Improved Measurements of the Temperature and Polarization of the Cosmic Microwave Background from QUaD

Brown, M.L. and Ade, P. and Bock, J. and Bowden, M. and Cahill, G. and Castro, P.G. and Church, S. and Culverhouse, T. and Friedman, R.B. and Ganga, K. and Gear, W.K. and Gupta, S. and Hinderks, J. and Kovac, J. and Lange, A.E. and Leitch, E. and Melhuish, S.J. and Memari, Y. and Murphy, J.A. and Orlando, A. and O'Sullivan, C. and Piccirillo, L. and Pryke, C. and Rajguru, N. and Rusholme, B. and Schwarz, R. and Taylor, A.N. and Thompson, K.L. and Turner, A.H. and Wu, E.Y.S. and Zemcov, M. (2009) Improved Measurements of the Temperature and Polarization of the Cosmic Microwave Background from QUaD. The Astrophysical Journal, 705 (1). pp. 978-999. ISSN 0004-637X

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We present an improved analysis of the final data set from the QUaD experiment. Using an improved technique to remove ground contamination, we double the effective sky area and hence increase the precision of our cosmic microwave background (CMB) power spectrummeasurements by∼30%versus that previously reported. In addition, we have improved our modeling of the instrument beams and have reduced our absolute calibration uncertainty from 5% to 3.5% in temperature. The robustness of our results is confirmed through extensive jackknife tests, and by way of the agreement that we find between our two fully independent analysis pipelines. For the standard six-parameter ΛCDM model, the addition of QUaD data marginally improves the constraints on a number of cosmological parameters over those obtained from the WMAP experiment alone. The impact of QUaD data is significantly greater for a model extended to include either a running in the scalar spectral index, or a possible tensor component, or both. Adding both the QUaD data and the results from the Arcminute Cosmology Bolometer Array Receiver experiment, the uncertainty in the spectral index running is reduced by∼25% compared toWMAPalone, while the upper limit on the tensor-to-scalar ratio is reduced fromr < 0.48 tor < 0.33 (95% c.l.). This is the strongest limit on tensors to date from the CMBalone.We also use our polarizationmeasurements to place constraints on parity-violating interactions to the surface of last scattering, constraining the energy scale of Lorentz violating interactions to< 1.5×10−43 GeV (68% c.l.). Finally, we place a robust upper limit on the strength of the lensing B-mode signal. Assuming a single flat band power between = 200 and = 2000, we constrain the amplitude of B-modes to be < 0.57μK2 (95% c.l.).

Item Type: Article
Keywords: cosmic microwave background; cosmological parameters; cosmology observations; polarization;
Academic Unit: Faculty of Science and Engineering > Experimental Physics
Item ID: 2094
Depositing User: Dr. Anthony Murphy
Date Deposited: 18 Aug 2010 16:04
Journal or Publication Title: The Astrophysical Journal
Publisher: American Astronomical Society
Refereed: Yes

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