We determine the best-fit values and confidence limits for dynamical dark energy parameters together with other cosmological parameters on the basis of different datasets which include WMAP9 or Planck-2013 results on CMB anisotropy, BAO distance ratios from recent galaxy surveys, magnitude-redshift relations for distant SNe Ia from SNLS3 and Union2.1 samples and the HST determination of the Hubble constant. We use a Markov Chain Monte Carlo routine to map out the likelihood in the multi-dimensional parameter space. We show that the most precise determination of cosmological parameters with the narrowest confidence limits is obtained for the Planck{ +}HST{ +}BAO{ +}SNLS3 dataset. The best-fit values and 2$\sigma$ confidence limits for cosmological parameters in this case are $\Omega_{ de}=0.718\pm0.022$, $w_0=-1.15^{ +0.14}_{ -0.16}$, $c_a^2=-1.15^{ +0.02}_{ -0.46}$, $\Omega_bh^2=0.0220\pm0.0005$, $\Omega_{ cdm}h^2=0.121\pm0.004$, $h=0.713\pm0.027$, $n_s=0.958^{ +0.014}_{ -0.010}$, $A_s=(2.215^{ +0.093}_{ -0.101})\cdot10^{ -9}$, $\tau_{ rei}=0.093^{ +0.022}_{ -0.028}$. For this dataset, the $\Lambda$CDM model is just outside the 2$\sigma$ confidence region, while for the dataset WMAP9{ +}HST{ +}BAO{ +}SNLS3 the $\Lambda$CDM model is only 1$\sigma$ away from the best fit. The tension in the determination of some cosmological parameters on the basis of two CMB datasets WMAP9 and Planck-2013 is highlighted.
Categories: astro-ph.CO gr-qc