Constraining the dynamical dark energy parameters: Planck-2013 vs WMAP9

Abstract

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$\ddot{I}ƒ$ confidence limits for cosmological parameters in this case are $\hat{I}{\text{c◯}}_{de}=0.718\pm 0.022$, $w_0=-1.15_{-0.16}^{+0.14}$, $c_a^2=-1.15_{-0.46}^{+0.02}$, $\hat{I}{\text{c◯}}_b{h}^2=0.0220\pm 0.0005$, $\hat{I}{\text{c◯}}_{cdm}{h}^2=0.121\pm 0.004$, $h=0.713\pm 0.027$, $n_s=0.958_{-0.010}^{+0.014}$, $A_s=(2.215_{-0.101}^{+0.093})\cdot 10^{-9}$, $\ddot{I}{„}_{rei}=0.093_{-0.028}^{+0.022}$. For this dataset, the $\hat{I}›$CDM model is just outside the 2$\ddot{I}ƒ$ confidence region, while for the dataset WMAP9{+}HST{+}BAO{+}SNLS3 the $\hat{I}›$CDM model is only 1$\ddot{I}ƒ$ 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.

16 pages, 5 figures, 2 tables; accepted for publication in JCAP