Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Sky Maps, Systematic Errors, and Basic Results

(Abridged) New full sky temperature and polarization maps based on seven years of data from WMAP are presented. The new results are consistent with previous results, but have improved due to reduced noise from the additional integration time, improved knowledge of the instrument performance, and improved data analysis procedures. The improvements are described in detail. The seven year data set is well fit by a minimal six-parameter flat Lambda-CDM model. The parameters for this model, using the WMAP data in conjunction with baryon acoustic oscillation data from the Sloan Digital Sky Survey and priors on H_0 from Hubble Space Telescope observations, are: Omega_bh^2 = 0.02260 +-0.00053, Omega_ch^2 = 0.1123 +-0.0035, Omega_Lambda = 0.728 +0.015 -0.016, n_s = 0.963 +-0.012, tau = 0.087 +-0.014 and sigma_8 = 0.809 +-0.024 (68 % CL uncertainties). The temperature power spectrum signal-to-noise ratio per multipole is greater that unity for multipoles < 919, allowing a robust measurement of the third acoustic peak. This measurement results in improved constraints on the matter density, Omega_mh^2 = 0.1334 +0.0056 -0.0055, and the epoch of matter- radiation equality, z_eq = 3196 +134 -133, using WMAP data alone. The new WMAP data, when combined with smaller angular scale microwave background anisotropy data, results in a 3 sigma detection of the abundance of primordial Helium, Y_He = 0.326 +-0.075.The power-law index of the primordial power spectrum is now determined to be n_s = 0.963 +-0.012, excluding the Harrison-Zel'dovich-Peebles spectrum by >3 sigma. These new WMAP measurements provide important tests of Big Bang cosmology.Comment: 42 pages, 9 figures, Submitted to Astrophysical Journal Supplement Serie

Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Are There Cosmic Microwave Background Anomalies?

(Abridged) A simple six-parameter LCDM model provides a successful fit to WMAP data, both when the data are analyzed alone and in combination with other cosmological data. Even so, it is appropriate to search for any hints of deviations from the now standard model of cosmology, which includes inflation, dark energy, dark matter, baryons, and neutrinos. The cosmological community has subjected the WMAP data to extensive and varied analyses. While there is widespread agreement as to the overall success of the six-parameter LCDM model, various "anomalies" have been reported relative to that model. In this paper we examine potential anomalies and present analyses and assessments of their significance. In most cases we find that claimed anomalies depend on posterior selection of some aspect or subset of the data. Compared with sky simulations based on the best fit model, one can select for low probability features of the WMAP data. Low probability features are expected, but it is not usually straightforward to determine whether any particular low probability feature is the result of the a posteriori selection or of non-standard cosmology. We examine in detail the properties of the power spectrum with respect to the LCDM model. We examine several potential or previously claimed anomalies in the sky maps and power spectra, including cold spots, low quadrupole power, quadropole-octupole alignment, hemispherical or dipole power asymmetry, and quadrupole power asymmetry. We conclude that there is no compelling evidence for deviations from the LCDM model, which is generally an acceptable statistical fit to WMAP and other cosmological data.Comment: 19 pages, 17 figures, also available with higher-res figures on http://lambda.gsfc.nasa.gov; accepted by ApJS; (v2) text as accepte

Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Planets and Celestial Calibration Sources

(Abridged) We present WMAP seven-year observations of bright sources which are often used as calibrators at microwave frequencies. Ten objects are studied in five frequency bands (23 - 94 GHz): the outer planets (Mars, Jupiter, Saturn, Uranus and Neptune) and five fixed celestial sources (Cas A, Tau A, Cyg A, 3C274 and 3C58). The seven-year analysis of Jupiter provides temperatures which are within 1-sigma of the previously published WMAP five-year values, with slightly tighter constraints on variability with orbital phase, and limits (but no detections) on linear polarization. Scaling factors are provided which, when multiplied by the Wright Mars thermal model predictions at 350 micron, reproduce WMAP seasonally averaged observations of Mars within ~2%. An empirical model is described which fits brightness variations of Saturn due to geometrical effects and can be used to predict the WMAP observations to within 3%. Seven-year mean temperatures for Uranus and Neptune are also tabulated. Uncertainties in Uranus temperatures are 3%-4% in the 41, 61 and 94 GHz bands; the smallest uncertainty for Neptune is ~8% for the 94 GHz band. Intriguingly, the spectrum of Uranus appears to show a dip at ~30 GHz of unidentified origin, although the feature is not of high statistical significance. Flux densities for the five selected fixed celestial sources are derived from the seven-year WMAP sky maps, and are tabulated for Stokes I, Q and U, along with polarization fraction and position angle. Fractional uncertainties for the Stokes I fluxes are typically 1% to 3%. Source variability over the seven-year baseline is also estimated. Significant secular decrease is seen for Cas A and Tau A: our results are consistent with a frequency independent decrease of about 0.53% per year for Cas A and 0.22% per year for Tau A.Comment: 72 pages, 21 figures; accepted to ApJS; (v2) corrected Mars model scaling factors, added figure 21, added text to Mars, Saturn and celestial sources section

Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results

We present new full-sky temperature and polarization maps in five frequency bands from 23 to 94 GHz, based on data from the first five years of the WMAP sky survey. The five-year maps incorporate several improvements in data processing made possible by the additional years of data and by a more complete analysis of the instrument calibration and in-flight beam response. We present several new tests for systematic errors in the polarization data and conclude that Ka band data (33 GHz) is suitable for use in cosmological analysis, after foreground cleaning. This significantly reduces the overall polarization uncertainty. With the 5 year WMAP data, we detect no convincing deviations from the minimal 6-parameter LCDM model: a flat universe dominated by a cosmological constant, with adiabatic and nearly scale-invariant Gaussian fluctuations. Using WMAP data combined with measurements of Type Ia supernovae and Baryon Acoustic Oscillations, we find (68% CL uncertainties): Omega_bh^2 = 0.02267 \pm 0.00059, Omega_ch^2 = 0.1131 \pm 0.0034, Omega_Lambda = 0.726 \pm 0.015, n_s = 0.960 \pm 0.013, tau = 0.084 \pm 0.016, and Delta_R^2 = (2.445 \pm 0.096) x 10^-9. From these we derive: sigma_8 = 0.812 \pm 0.026, H_0 = 70.5 \pm 1.3 km/s/Mpc, z_{reion} = 10.9 \pm 1.4, and t_0 = 13.72 \pm 0.12 Gyr. The new limit on the tensor-to-scalar ratio is r < 0.22 (95% CL). We obtain tight, simultaneous limits on the (constant) dark energy equation of state and spatial curvature: -0.14 < 1+w < 0.12 and -0.0179 < Omega_k < 0.0081 (both 95% CL). The number of relativistic degrees of freedom (e.g. neutrinos) is found to be N_{eff} = 4.4 \pm 1.5, consistent with the standard value of 3.04. Models with N_{eff} = 0 are disfavored at >99.5% confidence.Comment: 46 pages, 13 figures, and 7 tables. Version accepted for publication, ApJS, Feb-2009. Includes 5-year dipole results and additional references. Also available at http://lambda.gsfc.nasa.gov/product/map/dr3/map_bibliography.cf

The MAP Satellite Feed Horns

We present the design, manufacturing methods, and characterization of 20 microwave feed horns currently in use on the Microwave Anisotropy Probe (MAP) satellite. The nature of the cosmic microwave background (CMB) anisotropy requires a detailed understanding of the properties of every optical component of a microwave telescope. In particular, the properties of the feeds must be known so that the forward gain and sidelobe response of the telescope can be modeled and so that potential systematic effects may be computed. MAP requires low emissivity, azimuthally symmetric, low-sidelobe feeds in five microwave bands (K, Ka, Q, V, and W) that fit within a constrained geometry. The beam pattern of each feed is modeled and compared with measurements; the agreement is generally excellent to the -60 dB level (80 degrees from the beam peak). This agreement verifies the beam-predicting software and the manufacturing process. The feeds also affect the properties and modeling of the microwave receivers. To this end, we show that the reflection from the feeds is less than -25 dB over most of each band and that their emissivity is acceptable. The feeds meet their multiple requirements.Comment: 9 pages with 7 figures, of which 2 are in low-resolution versions; paper is available with higher quality figures at http://map.gsfc.nasa.gov/m_mm/tp_links.htm

Constraints on the Polarization of the Anomalous Microwave Emission in the Perseus Molecular Complex from 7-year WMAP data

We have used the seven year Wilkinson Microwave Anisotropy Probe (WMAP) data in order to update the measurements of the intensity signal in the G159.6-18.5 region within the Perseus Molecular Complex, and to set constraints on the polarization level of the anomalous microwave emission in the frequency range where this emission is dominant. At 23, 33 and 41 GHz, we obtain upper limits on the fractional linear polarization of 1.0, 1.8 and 2.7% respectively (with a 95 per cent confidence level). These measurements rule out a significant number of models based on magnetic dipole emission of grains that consist of a simple domain (Draine & Lazarian 1999) as responsible of the anomalous emission. When combining our results with the measurement obtained with the COSMOSOMAS experiment at 11 GHz (Battistelli et al. 2006), we find consistency with the predictions of the electric dipole and resonance relaxation theory (Lazarian & Draine 2000) at this frequency range.Comment: 14 pages, 7 figures, ApJ submitte

Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Angular Power Spectra

We present the temperature and polarization angular power spectra of the cosmic microwave background (CMB) derived from the first 5 years of WMAP data. The 5-year temperature (TT) spectrum is cosmic variance limited up to multipole l=530, and individual l-modes have S/N>1 for l<920. The best fitting six-parameter LambdaCDM model has a reduced chi^2 for l=33-1000 of chi^2/nu=1.06, with a probability to exceed of 9.3%. There is now significantly improved data near the third peak which leads to improved cosmological constraints. The temperature-polarization correlation (TE) is seen with high significance. After accounting for foreground emission, the low-l reionization feature in the EE power spectrum is preferred by \Delta\chi^2=19.6 for optical depth tau=0.089 by the EE data alone, and is now largely cosmic variance limited for l=2-6. There is no evidence for cosmic signal in the BB, TB, or EB spectra after accounting for foreground emission. We find that, when averaged over l=2-6, l(l+1)C^{BB}_l/2\pi < 0.15 uK^2 (95% CL).Comment: 29 pages, 13 figures, accepted by ApJ