Impact of three years of data from the Wilkinson Microwave Anisotropy Probe on cosmological models with dynamical dark energy

The first three years of observation of the Wilkinson Microwave Anisotropy Probe (WMAP) have provided the most precise data on the anisotropies of the cosmic microwave background (CMB) to date. We investigate the impact of these results and their combination with data from other astrophysical probes on cosmological models with a dynamical dark energy component. By considering a wide range of such models, we find that the constraints on dynamical dark energy are significantly improved compared to the first year data.

Figure 1

Monte Carlo results for the cosmological parameters. The left-hand side shows the 1$\sigma$ confidence intervals for the comparison of the models to the 3-year data of WMAP, the right-hand side corresponds to the results for the analysis with the combined set II. The shaded regions depict the 1$\sigma$ intervals for the $\Lambda$-CDM analysis from WMAP for the WMAP data only and the “all” set, respectively. The crosses show the value of the respective parameter for the best fit model in the Monte Carlo chains.

Figure 2

One-sigma confidence intervals for the fraction of dark energy at different redshifts for the interpolated model. Red is the result obtained by comparing to the WMAP 3-year data, blue (lower) corresponds to the combined set II as described in the text. The black line shows the evolution of ${\Omega }_{\Lambda }$ for a $\Lambda$-CDM universe with the WMAP 3-year best fit values for the standard cosmological parameters.