Constraints on dark energy from new observations including PanSTARRS
Abstract
In this paper, we set the new limits on the equation of state parameter (EoS) of dark energy with the observations of cosmic microwave background radiation (CMB) from Planck satellite, the type Ia supernovae from PanSTARRS and the baryon acoustic oscillation (BAO). We consider two parametrization forms of EoS: a constant w and time evolving w(a)=w_{0}+w_{a}(1a). The results show that with a constant EoS, w=1.141±0.075 68% C.L.), which is consistent with ΛCDM at about 2σ confidence level. For a time evolving w(a) model, we get w_{0}=1.09^{+0.16}_{0.18} 1σ C.L.), w_{a}=0.34^{+0.87}_{0.51} 1σ C.L.), and in this case ΛCDM can be comparable with our observational data at 1σ confidence level. In order to do the parametrization independent analysis, additionally we adopt the so called principal component analysis (PCA) method, in which we divide redshift range into several bins and assume w as a constant in each redshift bin (binw). In such binw scenario, we find that for most of the bins cosmological constant can be comparable with the data, however, there exists few bins which give w deviating from ΛCDM at more than 2σ confidence level, which shows a weak hint for the time evolving behavior of dark energy. To further confirm this hint, we need more data with higher precision.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 August 2014
 DOI:
 10.1088/14757516/2014/08/030
 arXiv:
 arXiv:1405.2724
 Bibcode:
 2014JCAP...08..030Z
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 9 pages, 8 figures, 1 table