SEVEN-YEAR WILKINSON MICROWAVE ANISOTROPY PROBE (WMAP) OBSERVATIONS: POWER SPECTRA AND WMAP-DERIVED PARAMETERS

By D. Larson, J. Dunkley, Gary F. Hinshaw, E. Komatsu, M. Nolta, C. Bennett, B. Gold, Mark Halpern, R. Hill, N. Jarosik and 11 more. 2010

1,522 citations recorded by the source corpus.

The WMAP mission has produced sky maps from seven years of observations at L2. We present the angular power spectra derived from the seven-year maps and discuss the cosmological conclusions that can be inferred from WMAP data alone. With the seven-year data, the temperature (TT) spectrum measurement has a signal-to-noise ratio per multipole that exceeds unity for l < 919; and in band powers of width Δl = 10, the signal-to-noise ratio exceeds unity up to l = 1060. The third acoustic peak in the TT spectrum is now well measured by WMAP. In the context of a flat ΛCDM model, this improvement allows us to place tighter constraints on the matter density from WMAP data alone, Ωmh2 = 0.1334+0.0056−0.0055, and on the epoch of matter-radiation equality, zeq = 3196+134−133. The temperature-polarization (TE) spectrum is detected in the seven-year data with a significance of 20σ, compared to 13σ with the five-year data. We now detect the second dip in the TE spectrum near l ∼ 450 with high confidence. The TB and EB spectra remain consistent with zero, thus demonstrating low systematic errors and foreground residuals in the data. The low-l EE spectrum, a measure of the optical depth due to reionization, is detected at 5.5σ significance when averaged over l = 2–7: l(l + 1)CEEl/(2π) = 0.074+0.034−0.025 μK2 (68% CL). We now detect the high-l, 24 ⩽ l ⩽ 800, EE spectrum at over 8σ. The BB spectrum, an important probe of gravitational waves from inflation, remains consistent with zero; when averaged over l = 2–7, l(l + 1)CBBl/(2π) < 0.055 μK2 (95% CL). The upper limit on tensor modes from polarization data alone is a factor of two lower with the seven-year data than it was using the five-year data. The data remain consistent with the simple ΛCDM model: the best-fit TT spectrum has an effective χ2 of 1227 for 1170 degrees of freedom, with a probability to exceed of 9.6%. The allowable volume in the six-dimensional space of ΛCDM parameters has been reduced by a factor of 1.5 relative to the five-year volume, while the ΛCDM model that allows for tensor modes and a running scalar spectral index has a factor of three lower volume when fit to the seven-year data. We test the parameter recovery process for bias and find that the scalar spectral index, ns, is biased high, but only by 0.09σ, while the remaining parameters are biased by <0.15σ. The improvement in the third peak measurement leads to tighter lower limits from WMAP on the number of relativistic degrees of freedom (e.g., neutrinos) in the early universe: Neff>2.7(95%CL). Also, using WMAP data alone, the primordial helium mass fraction is found to be YHe = 0.28+0.14−0.15, and with data from higher-resolution cosmic microwave background experiments included, we now establish the existence of pre-stellar helium at >3σ. These new WMAP measurements provide important tests of big bang cosmology.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/d5318bf9f74ae1e5ea794ca25f29f27bd5435e31

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Atomic and Molecular Physics, and Optics

In Instrumentation

Citations in the corpus

Trans-Planckian issues for inflationary cosmology (2012, methodology): “This can also been done with the help of the CMB anisotropies that have been precisely measured by the WMAP satellite [75, 76] (see Fig.”
KECK SPECTROSCOPY OF 3 < z < 7 FAINT LYMAN BREAK GALAXIES: THE IMPORTANCE OF NEBULAR EMISSION IN UNDERSTANDING THE SPECIFIC STAR FORMATION RATE AND STELLAR MASS DENSITY (2012, methodology): “The UV output implied by the mass density is in principle sufficient to achieve reionization by z ≃ 6 − 8 but struggles to account for the optical depth to electron scattering implied by WMAP (e.g., Larson et al. 2011).”
MontePython 3: Boosted MCMC sampler and other features (2018, background): “0 D [61] wmap 9yr WMAP 9yr (own wrapper) CMB 1.”
The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: analysis of potential systematics (2012, methodology): “This is the same cosmology as of White et al. (2011) and is close to 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) parameters (Larson et al. 2011).”
The clustering of galaxies in the sdss-iii baryon oscillation spectroscopic survey: Baryon acoustic oscillations in the data release 9 spectroscopic galaxy sample (2012, methodology): “Throughout the paper we assume a fiducial CDM+GR1 flat cosmological model with m = 0.274, h = 0.7, bh2 = 0.0224, ns = 0.95 and σ 8 = 0.8, similar to the best-fitting WMAP 7-year model (Komatsu et al. 2011; Larson et al. 2011).”
CHARACTERIZING THE CIRCUMGALACTIC MEDIUM OF NEARBY GALAXIES WITH HST/COS AND HST/STIS ABSORPTION-LINE SPECTROSCOPY (2012, methodology): “…of the baryonic mass (Mbar) in solar masses determined by assuming that a late-type galaxy contains the 5:1 cosmic ratio of dark matter to baryons (Larson et al. 2011); (4) the baryon fraction in stars and disk gas and dust (Fukugita, Hogan, & Peebles 1998; Peeples & Shankar 2011) as discussed…”
A MEASUREMENT OF THE COSMIC MICROWAVE BACKGROUND DAMPING TAIL FROM THE 2500-SQUARE-DEGREE SPT-SZ SURVEY (2012, methodology): “WMAP7 data alone have been used to constrain r < 0.36 at 95% confidence in the ΛCDM+r model (Larson et al. 2011).”
COSMOLOGICAL CONSTRAINTS FROM SUNYAEV–ZEL'DOVICH-SELECTED CLUSTERS WITH X-RAY OBSERVATIONS IN THE FIRST 178 deg2 OF THE SOUTH POLE TELESCOPE SURVEY (2011, methodology): “We use measurements of the CMB power spectrum from the seven-year Wilkinson Microwave Anisotropy Probe data release (WMAP7; Larson et al. 2011) and 790 deg2 of sky observed with the SPT (Keisler et al. 2011).”