Probing for dynamics of dark energy and curvature of universe with latest cosmological observations

Abstract

We use the newly released 182 Type Ia supernova data combined with the third-year Wilkinson Microwave Anisotropic Probe data (WMAP3) and large scale structure (LSS) information including SDSS and 2dFGRS to constrain the dark energy equation of state (EoS) as well as the curvature of universe $Ω_K$. Using the full dataset of Cosmic Microwave Background (CMB) and LSS rather than the shift parameter and linear growth factor, we make a Markov Chain Monte Carlo (MCMC) global fit, while paying particular attention to the dark energy perturbation. Parameterizing the EoS as $w_{DE}(a) = w_{0} + w_{1}(1-a)$, we find the best fit of ($w_0,w_1$) is ($-1.053,0.944$) and for $w_{DE}(a) = w_{0} + w_{1}\sin({3/2}π\ln(a))$, the best fit for ($w_0,w_1$) is ($-1.614,-1.046$). We find that a flat universe is a good approximation, namely, $|Ω_K|>0.06$ has been excluded by 2$σ$ yet the inclusion of $Ω_K$ can affect the measurement of DE parameters owing to their correlation and the present systematic effects of SNIa measurements.