NINE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE ( WMAP ) OBSERVATIONS: COSMOLOGICAL PARAMETER RESULTS

Abstract

We present cosmological parameter constraints based on the final nine-year 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 ΛCDM model. When WMAP data are combined with measurements of the high-l cosmic microwave background (CMB) anisotropy, the baryon acoustic oscillation (BAO) scale, and the Hubble constant, the matter and energy densities, Ω b h 2 , Ω c h 2 , and Ω Λ , are each determined to a precision of ∼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 5σ 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 ΛCDM parameter space by a factor of 68,000 relative to pre-WMAP measurements. We investigate a number of data combinations and show that their ΛCDM 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 Ω k = −0.0027 +0.0039 −0.0038 ; the summed mass of neutrinos is limited to m ν < 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. 18 The map resolution levels refer to the HEALPix pixelization scheme (Gorski et al. 2005) where r4, r5, r9, and r10 refer to N side values of 16, 32, 512, and 1024, respectively. 19 these codes are available at http://lambda.gsfc.nasa.gov

The role of mergers and halo spin in shaping galaxy morphology

“…Our simulations were run with a Λ cold dark matter (ΛCDM) cosmological model with parameters Ωm = 0.2726, ΩΛ = 0.7274, Ω b = 0.0456, σ8 = 0.809, ns = 0.963, and h = 0.704, consistent with the nine-year Wilkinson Microwave Anisotropy Probe measurements (Hinshaw et al 2013). …”

Constraining thawing and freezing models with cluster number counts

“…However, we follow the normalization procedure of [37] in which the WMAP results are used [39,40]. Since we are mainly interested in differences of the predicted cluster number counts from thawing and freezing models, we put a flat prior on the cosmological parameters according to WMAP-9+BAO+H0 best fit values [40], i.e., H 0 = 69.33 Km/s/Mpc, Ω B0 h 2 = 0.02266, n s = 0.971 and σ 8,Λ = 0.83 with Ω CDM h 2 = 0.1157 to obtain the results for cluster number density. Once the number density per unit mass dn(M, z)/dM is known, it is easy to obtain the number of clusters per redshift interval dz above a given minimum (threshold) mass M = M min as…”

Estimation of inflation parameters for Perturbed Power Law model using recent CMB measurements

“…CMB power spectra for temperature and polarization is a window to the early era of the Universe and dynamics of the inflationary era can be studied with several observable quantities from CMB power spectra. Many single field inflationary models predict adiabatic, Gaussian and nearly scale independent perturbation and recent measurements from WMAP [4,5] and Planck [6] are consistent with these prediction. A detailed study for several single field inflationary model with the recent data from WMAP, Planck and BICEP-2 are done by Martin et al [7][8][9].…”