Planck 2015 Constraints on the Nonflat ϕCDM Inflation Model

Abstract

We perform Markov chain Monte Carlo analyses to put constraints on the nonflat ϕ CDM inflation model using Planck 2015 cosmic microwave background (CMB) anisotropy data and baryon acoustic oscillation distance measurements. The ϕ CDM 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- ϕ CDM 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.