Determination of Cosmological Parameters from Wilkinson Microwave Anisotropy Probe (WMAP) Observations

2004 ◽  
pp. 75-91 ◽  
Author(s):  
Eiichiro Komatsu
Keyword(s):  
Cosmological Parameters ◽  
Wilkinson Microwave Anisotropy Probe

scholarly journals First‐Year Wilkinson Microwave Anisotropy Probe ( WMAP ) Observations: Determination of Cosmological Parameters

2003 ◽  
Vol 148 (1) ◽  
pp. 175-194 ◽  
Author(s):  
D. N. Spergel ◽  
L. Verde ◽  
H. V. Peiris ◽  
E. Komatsu ◽  
M. R. Nolta ◽  
...  
Keyword(s):  
Cosmological Parameters ◽  
Wilkinson Microwave Anisotropy Probe ◽  
First Year

Compact radio sources and the determination of the cosmological parameters

1993 ◽  
Vol 10 (S) ◽  
pp. S251-S254 ◽  
Author(s):  
J Roland ◽  
P Charlot ◽  
J F Lestrade ◽  
G Miley ◽  
G Pelletier ◽  
...  
Keyword(s):  
Cosmological Parameters ◽  
Radio Sources

scholarly journals Reconstructing the Primordial Power Spectrum

2005 ◽  
Vol 216 ◽  
pp. 28-34
Author(s):  
S. L. Bridle ◽  
A. M. Lewis ◽  
J. Weller ◽  
G. Efstathiou
Keyword(s):  
Power Spectrum ◽  
Spectral Index ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Microwave Background ◽  
Primordial Power Spectrum ◽  
Initial Spectrum ◽  
Redshift Survey ◽  
Cosmic Microwave Background Data

We reconstruct the shape of the primordial power spectrum from the latest cosmic microwave background data, including the new results from the Wilkinson Microwave Anisotropy Probe (WMAP), and large scale structure data from the two degree field galaxy redshift survey (2dFGRS). We discuss two parameterizations taking into account the uncertainties in four cosmological parameters. First we parameterize the initial spectrum by a tilt and a running spectral index, finding marginal evidence for a running spectral index only if the first three WMAP multipoles (ℓ = 2, 3, 4) are included in the analysis. Secondly, to investigate further the low CMB large scale power, we modify the conventional power-law spectrum by introducing a scale above which there is no power. We find a preferred position of the cut at kc ∼ 3 × 10--4 Mpc--1 although kc = 0 (no cut) is not ruled out.

scholarly journals NONPARAMETRIC DETERMINATION OF REDSHIFT EVOLUTION INDEX OF DARK ENERGY

2007 ◽  
Vol 22 (21) ◽  
pp. 1569-1580 ◽  
Author(s):  
HOURI ZIAEEPOUR
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Cosmological Parameters ◽  
Positive Energy ◽  
Fundamental Constants ◽  
Geometrical Properties ◽  
Precise Data ◽  
Energy Models ◽  
Scaling Models

We propose a nonparametric method to determine the sign of γ — the redshift evolution index of dark energy. This is important for distinguishing between positive energy models, a cosmological constant, and what is generally called ghost models. Our method is based on geometrical properties and is more tolerant to uncertainties of other cosmological parameters than fitting methods in what concerns the sign of γ. The same parametrization can also be used for determining γ and its redshift dependence by fitting. We apply this method to SNLS supernovae and to gold sample of re-analyzed supernovae data from Riess et al. Both datasets show strong indication of a negative γ. If this result is confirmed by more extended and precise data, many of the dark energy models, including simple cosmological constant, standard quintessence models without interaction between quintessence scalar field(s) and matter, and scaling models are ruled out. We have also applied this method to Gurzadyan–Xue models with varying fundamental constants to demonstrate the possibility of using it to test other cosmologies.

scholarly journals Tachyon-polytropic inflation on the brane

Open Physics ◽  
2013 ◽  
Vol 11 (5) ◽  
Author(s):  
Mohammad Setare ◽  
Vahid Kamali
Keyword(s):  
Equation Of State ◽  
Cosmological Parameters ◽  
High Energy ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Inflationary Universe ◽  
Universe Model ◽  
Exponential Potential ◽  
Energy Limit ◽  
High Energy Limit ◽  
Slow Roll

AbstractWe consider the tachyon-brane inflationary universe model in the context of a polytropic gas equation of state. In slow-roll approximation, we discuss general conditions of this model. For exponential potential, in high-energy limit the characteristics of the model are presented. By using the seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) observational data, we constrain the cosmological parameters of the model.

scholarly journals THE EFFECT OF DIFFERENT OBSERVATIONAL DATA IN CONSTRAINING COSMOLOGICAL PARAMETERS

2012 ◽  
Vol 10 ◽  
pp. 85-94 ◽  
Author(s):  
YUNGUI GONG ◽  
QING GAO ◽  
ZONG-HONG ZHU
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Observational Data ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Model Parameters ◽  
Type Ia Supernova ◽  
Equation Of State Parameter ◽  
Type Ia

We use the SNLS3 compilation of 472 type Ia supernova data, the baryon acoustic oscillation measurement of distance, and the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe to study the effect of their different combinations on the fittings of cosmological parameters. Neither BAO nor WMAP7 data alone gives good constraint on the equation of state parameter of dark energy, but both WMAP7 data and BAO data help type Ia supernova data break the degeneracies among the model parameters, hence tighten the constraint on the variation of equation of state parameter wa, and WMAP7 data does the job a little better. Although BAO and WMAP7 data provide reasonably good constraints on Ωm and Ωk, it is not able to constrain the dynamics of dark energy, we need SNe Ia data to probe the property of dark energy, especially the variation of the equation of state parameter of dark energy. For the SNLS SNe Ia data, the nuisance parameters α and β are consistent for all different combinations of the above data. Their impacts on the fittings of cosmological parameters are minimal. ΛCDM model is consistent with current observational data.

AUTO- AND CROSS-CORRELATION OF PHASES OF THE WHOLE-SKY CMB AND FOREGROUND MAPS FROM THE 1-YEAR WMAP DATA

2006 ◽  
Vol 15 (08) ◽  
pp. 1283-1298 ◽  
Author(s):  
LUNG-YIH CHIANG ◽  
PAVEL D. NASELSKY
Keyword(s):  
Cross Correlation ◽  
Random Phase ◽  
Cosmological Parameters ◽  
Microwave Background ◽  
Return Mapping ◽  
Auto Correlation ◽  
Dimensional Uniformity ◽  
Cross Correlations ◽  
Wmap Data

The issue of non-Gaussianity is not only related to distinguishing the theories of the origin of primordial fluctuations, but also crucial for the determination of cosmological parameters in the framework of inflation paradigm. We present a method for testing non-Gaussianity on the whole-sky cosmic microwave background (CMB) anisotropies. This method is based on the Kuiper's statistic to probe the two-dimensional uniformity on a periodic mapping square associating phases: return mapping of phases of the derived CMB (similar to auto-correlation) and cross-correlations between phases of the derived CMB and foregrounds. Since phases reflect morphology, detection of cross-correlation of phases signifies the contamination of foreground signals in the derived CMB map. The advantage of this method is that one can cross-check the auto- and cross-correlation of phases of the derived maps and foregrounds, and mark off those multipoles in which the non-Gaussianity results from the foreground contaminations. We apply this statistic on the derived signals from the 1-year WMAP data. The auto-correlations of phases from the internal linear combination map show the significance above 95% C.L. against the random phase hypothesis on 17 spherical harmonic multipoles, among which some have pronounced cross-correlations with the foreground maps. We find that most of the non-Gaussianity found in the derived maps are from foreground contaminations. With this method we are better equipped to approach the issue of non-Gaussianity of primordial origin for the upcoming Planck mission.

scholarly journals Constraint on inflation model from BICEP2 and WMAP 9-year data

2015 ◽  
Vol 24 (04) ◽  
pp. 1541001 ◽  
Author(s):  
Cheng Cheng ◽  
Qing-Guo Huang
Keyword(s):  
Power Law ◽  
Hubble Space Telescope ◽  
Wave Spectrum ◽  
Cosmological Parameters ◽  
Acoustic Oscillation ◽  
Wilkinson Microwave Anisotropy Probe ◽  
Tensor Model ◽  
Scale Invariant ◽  
Inflation Model ◽  
Inverse Power Law

Even though Planck data released in 2013 (P13) is not compatible with Background Imaging of Cosmic Extragalactic Polarization (B2) and some local cosmological observations, including Supernova Legacy Survey (SNLS) samples and H0 prior from Hubble Space Telescope (HST) etc. Wilkinson Microwave Anisotropy Probe 9-year data (W9) is consistent with all of them in the base six-parameter ΛCDM + tensor cosmology quite well. In this paper, we adopt the combinations of B2+W9 and B2+W9+SNLS+BAO+HST to constrain the cosmological parameters in the base six-parameter ΛCDM + tensor model with nt = -r/8, where r and nt are the tensor-to-scalar ratio and the tilt of relic gravitational wave spectrum, and BAO denotes Baryon Acoustic Oscillation (BAO). We find that the Harrison–Zel'dovich (HZ) scale invariant scalar power spectrum is consistent with both data combinations, chaotic inflation is marginally disfavored by the data at around 2σ level, but the power-law inflation model and the inflation model with inverse power-law potential can fit the data nicely.

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