FIVE-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE OBSERVATIONS: LIKELIHOODS AND PARAMETERS FROM THE WMAP DATA

By J. Dunkley, E. Komatsu, M. Nolta, David N. Spergel, D. Larson, Gary F. Hinshaw, L. Page, C. Bennett, B. Gold, N. Jarosik and 9 more. 2008

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This paper focuses on cosmological constraints derived from analysis of WMAP data alone. A simple ΛCDM cosmological model fits the five-year WMAP temperature and polarization data. The basic parameters of the model are consistent with the three-year data and now better constrained: Ωbh2 = 0.02273 ± 0.00062, Ωch2 = 0.1099 ± 0.0062, ΩΛ = 0.742 ± 0.030, ns = 0.963+0.014−0.015, τ = 0.087 ± 0.017, and σ8 = 0.796 ± 0.036, with h = 0.719+0.026−0.027. With five years of polarization data, we have measured the optical depth to reionization, τ>0, at 5σ significance. The redshift of an instantaneous reionization is constrained to be zreion = 11.0 ± 1.4 with 68% confidence. The 2σ lower limit is zreion > 8.2, and the 3σ limit is zreion > 6.7. This excludes a sudden reionization of the universe at z = 6 at more than 3.5σ significance, suggesting that reionization was an extended process. Using two methods for polarized foreground cleaning we get consistent estimates for the optical depth, indicating an error due to the foreground treatment of τ ∼ 0.01. This cosmological model also fits small-scale cosmic microwave background (CMB) data, and a range of astronomical data measuring the expansion rate and clustering of matter in the universe. We find evidence for the first time in the CMB power spectrum for a nonzero cosmic neutrino background, or a background of relativistic species, with the standard three light neutrino species preferred over the best-fit ΛCDM model with Neff = 0 at >99.5% confidence, and Neff > 2.3(95%confidence limit (CL)) when varied. The five-year WMAP data improve the upper limit on the tensor-to-scalar ratio, r < 0.43(95%CL), for power-law models, and halve the limit on r for models with a running index, r < 0.58(95%CL). With longer integration we find no evidence for a running spectral index, with dns/dln k = −0.037 ± 0.028, and find improved limits on isocurvature fluctuations. The current WMAP-only limit on the sum of the neutrino masses is ∑mν < 1.3 eV(95%CL), which is robust, to within 10%, to a varying tensor amplitude, running spectral index, or dark energy equation of state.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/5c4250a9aae78dbf04f36c6151d64df27d24d940

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Citations in the corpus

Cosmological constraints from a combination of galaxy clustering and lensing – I. Theoretical framework (2012, background): “…et al. 2003) have yielded constraints on various cosmological parameters at the few percent level (Spergel et al. 2003, ⋆ E-mail: frank.vandenbosch@yale.edu 2007; Dunkley et al. 2009; Komatsu et al. 2009, 2011), and ongoing experiments, such as PLANCK, will tighten these constraints even further.”
Galaxies at z = 6 - 9 from the WFC3/IR imaging of the HUDF (2009, methodology): “A key goal of modern observational cosmology is to discover and study the first galaxies, and to quantify their role in the reionisation of the neutral universe at redshiftsz > 7 (Dunkley et al., 2009).”
RADIATION PRESSURE FROM MASSIVE STAR CLUSTERS AS A LAUNCHING MECHANISM FOR SUPER-GALACTIC WINDS (2010, background): “If the halo contained the cosmic abundance of baryons, Mb ≈ 0.173Mh (Dunkley et al. 2009), the mean column of hot gas would beNH ∼ 3× 1019cm−2.”
STELLAR AND TOTAL BARYON MASS FRACTIONS IN GROUPS AND CLUSTERS SINCE REDSHIFT 1 (2009, positive): “It has been measured to a very high precision from the 5 years Wilkinson Microwave Anisotropy Probe (WMAP5) observations of the Cosmic Microwave Background (CMB), giving a value of fWMAP5b = 0.171±0.009 (Dunkley et al. 2009)21.”
Cosmic chronometers: constraining the equation of state of dark energy. I: H(z) measurements (2009, positive): “The age-metallicity degeneracy is removed from spectra with blue-light coverage (2500–7500 Å) and modest S/N . we combine our measurements of H(z) with CMB data to derive constraints to cosmological parameters.”
STATISTICS OF 207 Lyα EMITTERS AT A REDSHIFT NEAR 7: CONSTRAINTS ON REIONIZATION AND GALAXY FORMATION MODELS (2010, background): “On the other hand, Dunkley et al. (2009) find that the polariza- 1 Observatories of the Carnegie Institution of Washington, 813 Santa Barbara St., Pasadena, CA 91101 2 Carnegie Fellow; ouchi at obs.carnegiescience.edu 3 Department of Astronomy, School of Science, University of Tokyo, Tokyo…”
The Observed Growth of Massive Galaxy Clusters II: X-ray Scaling Relations (2009, methodology): “…cluster gas mass fractions (A08, including the full 42 cluster data set), 5-yr CMB data from the Wilkinson Microwave Anisotropy Probe (WMAP5; Dunkley et al. 2009), the Type Ia supernova analysis of Kowalski et al. (2008, including their treatment of systematic errors) and the Baryon…”
UV CONTINUUM SLOPE AND DUST OBSCURATION FROM z ∼ 6 TO z ∼ 2: THE STAR FORMATION RATE DENSITY AT HIGH REDSHIFT (2009, result): “Although these parameters are slightly different from those determined from the WMAP five-year results (Dunkley et al. 2009), they allow for convenient comparison with other recent results expressed in a similar manner.”
Substructures in hydrodynamical cluster simulations (2008, result): “As such, the values ofΩm andσ8 in this model are somewhat higher than the best–fitting values obtained from the analysis of the 5-year WMAP data (Dunkley et al. 2008), but are still consistent with the current cosmological constraints.”