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Author(s): Hinshaw, G; Larson, D; Komatsu, E; Spergel, David N; Bennett, CL; et al

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Abstract: We present cosmological parameter constraints based on the final nine-year Wilkinson Microwave Anisotropy Probe (WMAP) data, in conjunction with a number of additional cosmological data sets. The WMAP data alone, and in combination, continue to be remarkably well fit by a six-parameter Delta CDM model. When WMAP data are combined with measurements of the high-l cosmic microwave background anisotropy, the baryon acoustic oscillation scale, and the Hubble constant, the matter and energy densities, Omega(b)h(2), Omega(c)h(2), and Omega(Lambda), are each determined to a precision of similar to 1.5%. The amplitude of the primordial spectrum is measured to within 3%, and there is now evidence for a tilt in the primordial spectrum at the 5 sigma level, confirming the first detection of tilt based on the five-year WMAP data. At the end of the WMAP mission, the nine-year data decrease the allowable volume of the six-dimensional Delta CDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their Delta CDM parameter fits are consistent. New limits on deviations from the six-parameter model are presented, for example: the fractional contribution of tensor modes is limited to r < 0.13 (95% CL); the spatial curvature parameter is limited to Omega(k) = -0.0027(-0.0038)(+0.0039); the summed mass of neutrinos is limited to Sigma m(nu) < 0.44 eV (95% CL); and the number of relativistic species is found to lie within N-eff = 3.84 +/- 0.40, when the full data are analyzed. The joint constraint on N-eff and the primordial helium abundance, Y-He, agrees with the prediction of standard big bang nucleosynthesis. We compare recent Planck measurements of the Sunyaev-Zel’dovich effect with our seven-year measurements, and show their mutual agreement. Our analysis of the polarization pattern around temperature extrema is updated. This confirms a fundamental prediction of the standard cosmological model and provides a striking illustration of acoustic oscillations and adiabatic initial conditions in the early universe.
Publication Date: Oct-2013
Electronic Publication Date: 20-Sep-2013
Citation: Hinshaw, G, Larson, D, Komatsu, E, Spergel, DN, Bennett, CL, Dunkley, J, Nolta, MR, Halpern, M, Hill, RS, Odegard, N, Page, L, Smith, KM, Weiland, JL, Gold, B, Jarosik, N, Kogut, A, Limon, M, Meyer, SS, Tucker, GS, Wollack, E, Wright, EL. (2013). NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: COSMOLOGICAL PARAMETER RESULTS. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 208 (10.1088/0067-0049/208/2/19
DOI: doi:10.1088/0067-0049/208/2/19
ISSN: 0067-0049
EISSN: 1538-4365
Type of Material: Journal Article
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.

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