Logo
ScienceStack
Explore
Plans and pricing
FAQ
Contact us
Table of Contents
Fetching ...
Sign In
Paper

Planck 2018 results. VI. Cosmological parameters

Abstract

We present cosmological parameter results from the final full-mission Planck measurements of the CMB anisotropies. We find good consistency with the standard spatially-flat 6-parameter CDM cosmology having a power-law spectrum of adiabatic scalar perturbations (denoted "base CDM" in this paper), from polarization, temperature, and lensing, separately and in combination. A combined analysis gives dark matter density , baryon density , scalar spectral index , and optical depth (in this abstract we quote confidence regions on measured parameters and on upper limits). The angular acoustic scale is measured to precision, with . These results are only weakly dependent on the cosmological model and remain stable, with somewhat increased errors, in many commonly considered extensions. Assuming the base-CDM cosmology, the inferred late-Universe parameters are: Hubble constant km/s/Mpc; matter density parameter ; and matter fluctuation amplitude . We find no compelling evidence for extensions to the base-CDM model. Combining with BAO we constrain the effective extra relativistic degrees of freedom to be , and the neutrino mass is tightly constrained to eV. The CMB spectra continue to prefer higher lensing amplitudes than predicted in base -CDM at over , which pulls some parameters that affect the lensing amplitude away from the base-CDM model; however, this is not supported by the lensing reconstruction or (in models that also change the background geometry) BAO data. (Abridged)