Planck 2015 Constraints on the Nonflat ϕCDM Inflation Model

Abstract

Abstract We perform Markov chain Monte Carlo analyses to put constraints on the nonflat ϕCDM inflation model using Planck 2015 cosmic microwave background (CMB) anisotropy data and baryon acoustic oscillation distance measurements. The ϕCDM model is a consistent dynamical dark energy model in which the currently accelerating cosmological expansion is powered by a scalar field ϕ slowly rolling down an inverse power-law potential energy density. We also use a physically consistent power spectrum for energy density inhomogeneities in this nonflat model. We find that, like the closed-ΛCDM and closed-XCDM models, the closed-ϕCDM model provides a better fit to the lower multipole region of the CMB temperature anisotropy data compared to that provided by the tilted flat-ΛCDM model. Also, like the other closed models, this model reduces the tension between the Planck and the weak lensing σ 8 constraints. However, the higher multipole region of the CMB temperature anisotropy data are better fit by the tilted flat-Λ model than by the closed models.