Olivier Doré

Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Implications for Cosmology

A simple cosmological model with only six parameters (matter density, � mh 2 , baryon density, � bh 2 , Hubble con- stant, H0, amplitude of fluctuations,� 8, optical depth,� , and a slope for the scalar perturbation spectrum, ns) fits not only the 3 year WMAP temperature and polarization data, but also small-scale CMB data, light element abundances, large-scalestructureobservations,andthesupernovaluminosity/distancerelationship.UsingWMAPdataonly,thebest- fit values for cosmological parameters for the power-law flatcold dark matter (� CDM) model are (� mh 2 ; � bh 2 ; h;ns;�;� 8) ¼(0:1277 þ0:0080 � 0:0079 ;0:02229 � 0:00073;0:732 þ0:031 � 0:032 ;0:958 � 0:016;0:089 � 0:030;0:761 þ0:049 � 0:048 ).The3year 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-Zeldovich-Peebles scale-invariant spectrum (ns ¼ 1; r ¼ 0). Adding additionaldatasetsimprovestheconstraintsonthesecomponentsandthespectralslope.Forpower-lawmodels,WMAP data alone puts an improved upper limit on the tensor-to-scalar ratio, r0:002 < 0:65 (95% CL) and the combination of WMAP and the lensing-normalized SDSS galaxy survey implies r0:002 < 0:30 (95% CL). Models that suppress large- scalepowerthrougharunningspectralindexoralarge-scalecutoffinthepowerspectrumareabetterfittotheWMAP and small-scale CMB data than the power-lawCDM model; however, the improvement in thefit to the WMAP data is only � � 2 ¼ 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) datayieldsasignificantconstraintontheequationofstateofthedarkenergy,w ¼� 0:967 þ0:073 � 0:072 .Ifweassumew ¼� 1, then the deviations from the critical density, � K, are small: the combination of WMAP and the SNLS data implies � k ¼� 0:011 � 0:012. The combination of WMAP 3 year data plus the HST Key Project constraint on H0 implies � k ¼� 0:014 � 0:017 and � � ¼ 0:716 � 0:055. Even if we do not include the prior that the universe is flat, by com- biningWMAP,large-scalestructure,andsupernovadata,wecanstillputastrongconstraintonthedarkenergyequation of state, w ¼� 1:08 � 0:12. For a flat universe, the combination of WMAP and other astronomical data yield a con- straint on the sum of the neutrino masses, P m� <0:66 eV (95%CL). Consistent with the predictions of simple infla- tionary 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.

Three year Wilkinson Microwave Anisotropy Probe (WMAP) observations: polarization analysis

The Wilkinson Microwave Anisotropy Probe (WMAP) has mapped the entire sky in five frequency bands between 23 and 94 GHz with polarization sensitive radiometers. We present three-year full-sky maps of the polarization and analyze them for foreground emission and cosmological implications. These observations open up a new window for understanding how the universe began and help set a foundation for future observations. WMAP observes significant levels of polarized foreground emission due to both Galactic synchrotron radiation and thermal dust emission. Synchrotron radiation is the dominant signal at l < 50 and ν . 40 GHz, while thermal dust emission is evident at 94 GHz. The least contaminated channel is at 61 GHz. We present a model of polarized foreground emission that captures the large angular scale characteristics of the microwave sky. After applying a Galactic mask that cuts 25.7% of the sky, we show that the high Galactic latitude rms polarized foreground emission, averaged over l = 4 − 6, ranges from ≈ 5 μK at 22 GHz to . 0.6 μK at 61 GHz. By comparison, the levels of intrinsic CMB polarization for a ΛCDM model with an optical depth of τ = 0.09 and assumed tensor to scalar ratio r = 0.3 are ≈ 0.3 μK for E-mode polarization and ≈ 0.03 μK for B-mode polarization. To analyze the maps for CMB polarization at l < 16, we subtract a model of the foreground emission. In the foreground corrected maps, we detect l(l+ 1)CEE l=<2−6>/2π = 0.086±0.029 (μK)2. This is interpreted as the result of rescattering of the CMB by free electrons released during reionization at zr = 10.9+2.7 −2.3 for a model with instantaneous reionization. By computing the likelihood of just the EE data as a function of τ we find τ = 0.10±0.03. When the same EE data are used in the full six parameter fit to all WMAP data (TT, TE, EE), we find τ = 0.09±0.03. We see no evidence for B-modes, limiting them to l(l+ 1)CBB l=<2−6>/2π = −0.04± 0.03 (μK)2. We perform a template fit to the E-mode and B-mode data with an approximate model for the tensor scalar ratio. We find that the limit from the polarization signals alone is r < 2.2 (95% CL) where r is evaluated at k = 0.002 Mpc−1. This corresponds to a limit on the cosmic density of gravitational waves of ΩGW h2 < 5×10−12. From the full WMAP analysis, we find r < 0.55 (95% CL) corresponding to a limit of ΩGW h2 < 1× 10−12 (95% CL). The limit on r is approaching the upper bound of predictions for some of the simplest models of inflation, r ∼ 0.3.

Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature Analysis

We present new full-sky temperature maps in five frequency bands from 23 to 94 GHz, based on data from the first 3 years of the WMAP sky survey. The new maps are consistent with the first-year maps and are more sensitive. The 3 year maps incorporate several improvements in data processing made possible by the additional years of data and by a more complete analysis of the polarization signal. These include several new consistency tests as well as refinements in the gain calibration and beam response models. We employ two forms of multifrequency analysis to separate astrophysical foreground signals from the CMB, each of which improves on our first-year analyses. First, we form an improved Internal Linear Combination (ILC) map, based solely on WMAP data, by adding a bias-correction step and by quantifying residual uncertainties in the resulting map. Second, we fit and subtract new spatial templates that trace Galactic emission; in particular, we now use low-frequency WMAP data to trace synchrotron emission instead of the 408 MHz sky survey. The WMAP point source catalog is updated to include 115 new sources whose detection is made possible by the improved sky map sensitivity. We derive the angular power spectrum of the temperature anisotropy using a hybrid approach that combines a maximum likelihood estimate at low l (large angular scales) with a quadratic cross-power estimate for l > 30. The resulting multifrequency spectra are analyzed for residual point source contamination. At 94 GHz the unmasked sources contribute 128 ± 27 μK2 to l(l + 1)Cl/2π at l = 1000. After subtracting this contribution, our best estimate of the CMB power spectrum is derived by averaging cross-power spectra from 153 statistically independent channel pairs. The combined spectrum is cosmic variance limited to l = 400, and the signal-to-noise ratio per l-mode exceeds unity up to l = 850. For bins of width Δl/l = 3%, the signal-to-noise ratio exceeds unity up to l = 1000. The first two acoustic peaks are seen at l = 220.8 ± 0.7 and l = 530.9 ± 3.8, respectively, while the first two troughs are seen at l = 412.4 ± 1.9 and l = 675.2 ± 11.1. The rise to the third peak is unambiguous; when the WMAP data are combined with higher resolution CMB measurements, the existence of a third acoustic peak is well established. Spergel et al. use the 3 year temperature and polarization data to constrain cosmological model parameters. A simple six-parameter ΛCDM model continues to fit CMB data and other measures of large-scale structure remarkably well. The new polarization data produce a better measurement of the optical depth to reionization, τ = 0.089 ± 0.03. This new and tighter constraint on τ helps break a degeneracy with the scalar spectral index, which is now found to be ns = 0.960 ± 0.016. If additional cosmological data sets are included in the analysis, the spectral index is found to be ns = 0.947 ± 0.015.

Probing dark energy perturbations: The Dark energy equation of state and speed of sound as measured by WMAP

We review the implications of having a nontrivial matter component in the Universe and the potential for detecting such a component through the matter power spectrum and integrated Sachs-Wolfe effect. We adopt a phenomenological approach and consider the mysterious dark energy to be a cosmic fluid. It is thus fully characterized, up to linear order, by its equation of state and its speed of sound. Whereas the equation of state has been widely studied in the literature, less interest has been devoted to the speed of sound. Its observational consequences come predominantly from very large scale modes of dark matter perturbations

Three-Year Wilkinson Microwave Anisotropy Probe (WMAP)* Observations: Beam Profiles, Data Processing, Radiometer Characterization, and Systematic Error Limits

(kl0.01h{mathrm{Mpc}}^{ensuremath{-}1}).

Are Chaplygin gases serious contenders to the dark energy throne

Since these modes have hardly been probed so far by large scale galaxy surveys, we investigate whether joint constraints can be placed on those two quantities using the recent cosmic microwave background (CMB) fluctuations measurements by the Wilkinson Microwave Anisotropy Probe as well as the recently measured CMB large scale structure cross correlation. We find only a tentative 1 sigma detection of the speed of sound, from CMB alone,

Three-Year Wilkinson Microwave Anisotropy Probe (WMAP)* Observations: Foreground Polarization

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Skeleton as a probe of the cosmic web: the two-dimensional case

at this low significance level. Furthermore, the current uncertainties in bias in the matter power spectrum preclude any constraints being placed using the cross correlation of CMB with the NRAO VLA Sky Survey radio survey.

The Cosmic Microwave Background Quadrupole in a Polarized Light

The WMAP satellite has completed 3 years of observations of the cosmic microwave background radiation. The 3yeardataproductsincludeseveralsetsof fullskymapsoftheStokesI,Q,andUparametersinfivefrequencybands, spanning 23Y94 GHz, and supporting items such as beam window functions and noise covariance matrices. The processing used to produce the current sky maps and supporting products represents a significant advancement over the first-year analysis and is described herein. Improvements to the pointing reconstruction, radiometer gain modeling, window function determination, and radiometer spectral noise parameterization are presented. A detailed description of the updated data processing that produces maximum likelihood sky map estimates is presented, along withthemethodsusedtoproducereducedresolutionmapsandcorrespondingnoisecovariancematrices.Finally,two methods used to evaluate the noise of the full resolution sky maps are presented along with several representativeyear-to-yearnulltests,demonstratingthatskymapsproducedfromdatafromdifferentobservationalepochsare consistent. Subject headingg cosmic microwave background — instrumentation: detectors — space vehicles: instruments

Beyond the Damping Tail: Cross-Correlating the Kinetic Sunyaev-Zel’dovich Effect with Cosmic Shear

We study the implications on both background and perturbation evolution of introducing a Chaplygin gas component in the universes ingredients. We perform likelihood analyses using wide-ranging, SN1a, CMB and large scale structure observations to assess whether such a component could be a genuine alternative to a cosmological constant. We find that current data favors an adiabatic Chaplygin gas with behavior akin to a cosmological constant.