Cheng Cheng, Qing-Guo Huang
In this paper we investigate three kinds of dark energy models: $\Lambda$CDM, $w$CDM and (CPL)CDM model with/without dark radiation respectively, and check whether they can fit the data from Planck, WMAP Polarization (WP), baryon acoustic oscillation (BAO), the combination of supernova Union2.1 compilation of 580 SNe (Union2.1), Supernova Legacy Survey (SNLS) and $H_0$ prior from Hubble Space Telescope (HST) project. In $\Lambda$CDM model, even though the tension on $H_0$ between Planck and $H_0$ prior from HST project can be relaxed if the dark radiation is introduced ($\Delta N_{\rm eff}=0.536_{-0.224}^{+0.229}$ at 68% CL; Planck+WP+BAO+Union2.1+$H_0$), the tension on $\Omega_m$ between Planck and SNLS still exists. In $w$CDM model, the constraints on $\Omega_m$ and $H_0$ from Planck, Union2.1 and SNLS are broadened, and then those tensions in $\Lambda$CDM model are relieved. However, in the (CPL)CDM model, Union2.1 prefers a quite large amount of matter in the Universe which indicates a discrepancy with Planck+WP estimate at around $2.3\sigma$ level. Combining Planck+WP, BAO and SNLS+$H_0$, a cosmological constant is disfavoured at more than $1\sigma$, but still stays within the $2\sigma$ confidence region. We conclude that there is no evidence for a dynamical dark energy and dark radiation in (CPL)CDM model.
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http://arxiv.org/abs/1306.4091
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