Acoustic Peaks and Dips in the Cosmic Microwave Background Power Spectrum: Observational Data and Cosmological Constraints

Durrer, Ruth; Novosyadlyj, B.; Apunevych, S.

doi:10.1086/345079

Cited by 41 publications

(56 citation statements)

References 39 publications

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“…This cosmic acceleration has also been confirmed, independent of the SNeIa magnitude-redshift relation, by observations of cosmic microwave background anisotropies (Wilkinson Microwave Anisotropy Probe [WMAP]: Bennett et al 2003;Durrer et al 2003;andSpergel et al 2003, 2006) and the large scale structure (LSS) in the distribution of galaxies (Sloan Digital Sky Survey [SDSS]; Tegmark et al 2006). …”

Section: Introductionmentioning

confidence: 77%

Testing power-law cosmology with galaxy clusters

Zhu

Hu²,

Alcaniz

et al. 2008

A&A

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Aims. Power-law cosmologies, in which the cosmological scale factor evolves as a power law in time, a ∝ t α with α > ∼ 1, regardless of the matter content or cosmological epoch, is comfortably concordant with a host of cosmological observations. Methods. In this article, we use recent measurements of the X-ray gas mass fractions in clusters of galaxies to constrain the α parameter with curvature k = ±1, 0. Results. We find that the best fit happens for an open scenario with the power index α = 1.14 ± 0.05, though the flat and closed model cannot be ruled out with high confidence. Conclusions. Our results are in agreement with other recent analyses and show that the X-ray gas mass fraction measurements in clusters of galaxies provide a complementary test of the power-law cosmology.

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Section: Introductionmentioning

confidence: 77%

Testing power-law cosmology with galaxy clusters

Zhu

Hu²,

Alcaniz

et al. 2008

A&A

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“…The amplitude of these shifts only depends on the matter and baryon densities, on the redshift of recombination, on the scalar spectral index for primordial fluctuations and on the density of Dark Energy at the time of last scattering. Parameterization formulae for φ m are given in [60,62]. They depend on the following set of parameters: the matter density Ω D 0 m , the baryon density…”

Section: Computation Of Observablesmentioning

confidence: 99%

Testing backreaction effects with observations

et al. 2009

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Abstract. In order to quantitatively test the ability of averaged inhomogeneous cosmologies to correctly describe observations of the large scale properties of the Universe, we introduce a smoothed template metric corresponding to a constant spatial curvature model at any time, but with an evolving curvature parameter. This metric is used to compute quantities along an approximate effective lightcone of the averaged model of the Universe. As opposed to the standard Friedmann model, we parameterize this template metric by exact scaling properties of an averaged inhomogeneous cosmology, and we also motivate this form of the metric by results on a geometrical smoothing of inhomogeneous cosmological hypersurfaces. The purpose of the paper is not to demonstrate that the backreaction effect is actually responsible for the Dark Energy phenomenon by explicitly calculating the effect from a local model of the geometry and the distribution of matter, but rather to propose a way to deal with observations in the backreaction context, and to understand what kind of generic properties have to hold in order for a backreaction model to explain the observed features of the Universe on large scales. We test our hypothesis for the template metric against supernova data and the position of the CMB peaks, and infer the goodness-of-fit and parameter uncertainties. We find that averaged inhomogeneous models can reproduce the observations without requiring an additional Dark Energy component (though a volume acceleration is still needed), and that current data do not disfavour our main assumption on the effective lightcone structure. We also show that the experimental uncertainties on the angular diameter distance and the Hubble parameter from Baryon Acoustic Oscillations measurements -forseen in future surveys like the proposed EUCLID satellite project -are sufficiently small to distinguish between a FLRW template geometry and the template geometry with consistently evolving curvature.

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“…(62) and (63) for the temperature SW plateau and requiring that the COBE constraint in Eq. (64) is fulfilled.…”

Section: A Toy Model For the Cmbrmentioning

confidence: 99%

Constraints on a mixed inflaton and curvaton scenario for the generation of the curvature perturbation

2004

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We consider a simple supersymmetric grand unified model which naturally solves the strong CP and µ problems via a Peccei-Quinn symmetry and leads to the standard realization of hybrid inflation. We show that the Peccei-Quinn field of this model can act as a curvaton. In contrast to the standard curvaton hypothesis, both the inflaton and the curvaton contribute to the total curvature perturbation. The model predicts the existence of an isocurvature perturbation too which has mixed correlation with the adiabatic one. The cold dark matter of the universe is mostly constituted by axions, which are produced at the QCD phase transition, plus a small amount of lightest sparticles. The predictions of the model are confronted with the first-year Wilkinson microwave anisotropy probe and other cosmic microwave background radiation data. We analyze in detail two representative choices of parameters for our model and derive bounds on the curvaton contribution to the adiabatic perturbation. We find that, for the choice which provides the best fitting of the data, the curvaton contribution to the amplitude of the adiabatic perturbation must be smaller than about 67% and the amplitude of the partial curvature perturbation from the curvaton smaller than 43.2 × 10 −5 (both at 95% confidence level). The best-fit power spectra are dominated by the adiabatic part of the inflaton contribution. We use Bayesian model comparison to show that this choice of parameters is disfavored with respect to the pure inflaton scale-invariant case with odds of about 50 to 1. For the second choice of parameters examined, the adiabatic mode is dominated by the curvaton, but this choice is strongly disfavored relative to the pure inflaton scale-invariant case (with odds of about 10 7 to 1). We conclude that in the present framework the perturbations must be dominated by the adiabatic component from the inflaton.

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Acoustic Peaks and Dips in the Cosmic Microwave Background Power Spectrum: Observational Data and Cosmological Constraints

Cited by 41 publications

References 39 publications

Testing power-law cosmology with galaxy clusters

Testing power-law cosmology with galaxy clusters

Testing backreaction effects with observations

Constraints on a mixed inflaton and curvaton scenario for the generation of the curvature perturbation

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