Improved cosmological constraints on the curvature and equation of state of dark energy

Abstract

We apply the Constitution compilation of 397 supernova Ia, the baryon acoustic oscillation measurements including the $A$ parameter, the distance ratio and the radial data, the five-year Wilkinson microwave anisotropy probe and the Hubble parameter data to study the geometry of the universe and the property of dark energy by using the popular Chevallier-Polarski-Linder and Jassal-Bagla-Padmanabhan parameterizations. We compare the simple ${\chi }^2$ method of joined contour estimation and the Monte Carlo Markov chain method, and find that it is necessary to make the marginalized analysis on the error estimation. The probabilities of ${\Omega }_k$ and $w_a$ in the Chevallier-Polarski-Linder model are skew distributions, and the marginalized $1\sigma$ errors are ${\Omega }_m=0.279_{-0.008}^{+0.015}$, ${\Omega }_k=0.005_{-0.011}^{+0.006}$, $w_0=-1.05_{-0.06}^{+0.23}$, and $w_a=0.5_{-1.5}^{+0.3}$. For the Jassal-Bagla-Padmanabhan model, the marginalized $1\sigma$ errors are ${\Omega }_m=0.281_{-0.01}^{+0.015}$, ${\Omega }_k=0.000_{-0.006}^{+0.007}$, $w_0=-0.96_{-0.18}^{+0.25}$, and $w_a=-0.6_{-1.6}^{+1.9}$. The equation of state parameter $w(z)$ of dark energy is negative in the redshift range $0\le z\le 2$ at more than $3\sigma$ level. The flat $\Lambda$CDM model is consistent with the current observational data at the $1\sigma$ level.

10 figures, 12 pages, Classical and Quantum Gravity in press; v2 to match the pulished version

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• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
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• Thick gas discs in faint dwarf galaxies
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Cited by in corpus (13)

• Dark Energy
• Hubble parameter measurement constraints on dark energy
• Reconstruction of the Dark Energy equation of state
• Hubble parameter data constraints on dark energy
• Constraints on dark energy from H II starburst galaxy apparent magnitude versus redshift data
• Galaxy cluster number count data constraints on cosmological parameters
• Measurement on the cosmic curvature using the Gaussian process method
• Confronting Tracker Field Quintessence with Data
• The effect of different observational data on the constraints of cosmological parameters
• On the effect of the degeneracy between w_0 and w_a
• Forecasting cosmological parameter constraints from near-future space-based galaxy surveys
• Current cosmological constraints on the curvature, dark energy and modified gravity
• Constraints on Cosmological Models from Hubble Parameters Measurements