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2007ApJS..170..377S Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology Spergel, D. N.; Bean, R.; Dore, O.; Nolta, M. R.; Bennett, C. L.; Dunkley, J.; Hinshaw, G.; Jarosik, N.; Komatsu, E.; Page, L.; Peiris, H. V.; Verde, L.; Halpern, M.; Hill, R. S.; Kogut, A.; Limon, M.; Meyer, S. S.; Odegard, N.; Tucker, G. S.; Weiland, J. L.; Wollack, E.; Wright, E. L. Abstract. A simple cosmological model with only six parameters (matter density, Omega_m_h^2^, baryon density, Omega_b_h^2^, Hubble constant, H_0_, amplitude of fluctuations, sigma_8_, optical depth, tau, and a slope for the scalar perturbation spectrum, n_s_) fits not only the 3 year WMAP temperature and polarization data, but also small-scale CMB data, light element abundances, large-scale structure observations, and the supernova luminosity/distance relationship. Using WMAP data only, the best-fit values for cosmological parameters for the power-law flat Lambda cold dark matter (LambdaCDM) model are (Omega_m_h^2^,Omega_b_h^2^,h,n_s_,tau,sigma_8_)=(0.1277^+0.0080^_-0.0079_, 0.02229+/-0.00073,0.732^+0.031^_-0.032_,0.958+/-0.016,0.089+/-0.030,0.761^ +0.049^_-0.048_). The 3 year data dramatically shrink the allowed volume in this six-dimensional parameter space. Assuming that the primordial fluctuations are adiabatic with a power-law spectrum, the WMAP data alone require dark matter and favor a spectral index that is significantly less than the Harrison-Zel'dovich-Peebles scale-invariant spectrum (n_s_=1, r=0). Adding additional data sets improves the constraints on these components and the spectral slope. For power-law models, WMAP data alone puts an improved upper limit on the tensor-to-scalar ratio, r_0.002_<0.65 (95% CL) and the combination of WMAP and the lensing-normalized SDSS galaxy survey implies r_0.002_<0.30 (95% CL). Models that suppress large-scale power through a running spectral index or a large-scale cutoff in the power spectrum are a better fit to the WMAP and small-scale CMB data than the power-law LambdaCDM model; however, the improvement in the fit to the WMAP data is only Deltachi^2^=3 for 1 extra degree of freedom. Models with a running-spectral index are consistent with a higher amplitude of gravity waves. In a flat universe, the combination of WMAP and the Supernova Legacy Survey (SNLS) data yields a significant constraint on the equation of state of the dark energy, w=-0.967^+0.073^_-0.072_. If we assume w=-1, then the deviations from the critical density, Omega_K_, are small: the combination of WMAP and the SNLS data implies Omega_k_=-0.011+/-0.012. The combination of WMAP 3 year data plus the HST Key Project constraint on H_0_ implies Omega_k_=-0.014+/-0.017 and Omega_Lambda_=0.716+/-0.055. Even if we do not include the prior that the universe is flat, by combining WMAP, large-scale structure, and supernova data, we can still put a strong constraint on the dark energy equation of state, w=-1.08+/-0.12. For a flat universe, the combination of WMAP and other astronomical data yield a constraint on the sum of the neutrino masses, Sigmam_nu_<0.66 eV (95%CL). Consistent with the predictions of simple inflationary theories, we detect no significant deviations from Gaussianity in the CMB maps using Minkowski functionals, the bispectrum, trispectrum, and a new statistic designed to detect large-scale anisotropies in the fluctuations. Key words: Cosmology: Cosmic Microwave Background, Cosmology: Observations
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