http://arxiv.org/abs/1807.07421
We constrain tilted spatially-flat and untilted nonflat scalar field ($\phi$) dynamical dark energy inflation ($\phi$CDM) models by using Planck 2015 cosmic microwave background (CMB) anisotropy measurements and recent baryonic acoustic oscillation distances data, Type Ia supernovae apparent magnitude observations, Hubble parameter measurements, and growth rate data. We assume an inverse power-law scalar field potential energy density $V(\phi)=V_0 \phi^{-\alpha}$. We find that the combination of the CMB data with the four non-CMB data sets significantly improves parameter constraints, including strengthening the evidence for nonflatness in the untilted nonflat $\phi$CDM model from $1.8\sigma$ for the CMB data alone to more than $3.1\sigma$ for the combined data. In the untilted nonflat $\phi$CDM model current observations favor a spatially closed universe in which spatial curvature contributes about two-thirds of a percent of the current cosmological energy budget. The tilted flat $\phi$CDM model is a 0.4$\sigma$ better fit to the data than is the standard tilted flat $\Lambda$CDM model: current data is unable to rule out dynamical dark energy. The tilted nonflat $\phi$CDM model is more consistent with the Dark Energy Survey constraints on the current value of the rms amplitude of mass fluctuations ($\sigma_8$) as a function of the current value of the nonrelativistic matter density parameter ($\Omega_m$) but does not provide as good a fit to the smaller-angle CMB anisotropy data as does the standard tilted flat $\Lambda$CDM model. Some measured cosmological parameter values differ significantly when determined using the tilted flat and the untilted nonflat $\phi$CDM models, including the cold dark matter density parameter and the reionization optical depth.
C. Park and B. Ratra
Fri, 20 Jul 18
19/63
Comments: 21 pages, 14 figures, 5 tables. arXiv admin note: substantial text overlap with arXiv:1803.05522, arXiv:1801.00213
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