The evidence for a spatially flat Universe

2020/02/17 by George Efstathiou, Steven Gratton · 1 citation
Physics and Astronomy · #astro-ph.CO #hep-th

paper · pdf · doi:10.1093/mnrasl/slaa093

submitted to MNRAS

arxiv created 2020/02/17 · arxiv updated 2020/06/03

Abstract

We revisit the observational constraints on spatial curvature following recent claims that the Planck data favour a closed Universe. We use a new and statistically powerful Planck likelihood to show that the Planck temperature and polarization spectra are consistent with a spatially flat Universe, though because of a geometrical degeneracy cosmic microwave background spectra on their own do not lead to tight constraints on the curvature density parameter Omega_K. When combined with other astrophysical data, particularly geometrical measurements of baryon acoustic oscillations, the Universe is constrained to be spatially flat to extremely high precision, with Omega_ K = 0.0004 +/-0.0018 in agreement with the 2018 results of the Planck team. In the context of inflationary cosmology, the observations offer strong support for models of inflation with a large number of e-foldings and disfavour models of incomplete inflation.

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