Constraints on Λ CDM extensions from the SPT3G 2018 E E and T E power spectra
Abstract
We present constraints on extensions to the Λ CDM cosmological model from measurements of the E mode polarization autopower spectrum and the temperatureE mode crosspower spectrum of the cosmic microwave background (CMB) made using 2018 SPT3G data. The extensions considered vary the primordial helium abundance, the effective number of relativistic degrees of freedom, the sum of neutrino masses, the relativistic energy density and mass of a sterile neutrino, and the mean spatial curvature. We do not find clear evidence for any of these extensions, from either the SPT3G 2018 dataset alone or in combination with baryon acoustic oscillation and Planck data. None of these model extensions significantly relax the tension between Hubbleconstant, H_{0}, constraints from the CMB and from distanceladder measurements using Cepheids and supernovae. The addition of the SPT3G 2018 data to Planck reduces the squareroot of the determinants of the parameter covariance matrices by factors of 1.32.0 across these models, signaling a substantial reduction in the allowed parameter volume. We also explore CMBbased constraints on H_{0} from combined SPT, Planck, and ACT DR4 datasets. While individual experiments see some indications of different H_{0} values between the T T , T E , and E E spectra, the combined H_{0} constraints are consistent between the three spectra. For the full combined datasets, we report H_{0}=67.49 ±0.53 km s^{1} Mpc^{1} , which is the tightest constraint on H_{0} from CMB power spectra to date and in 4.1 σ tension with the most precise distanceladderbased measurement of H_{0}. The SPT3G survey is planned to continue through at least 2023, with existing maps of combined 2019 and 2020 data already having ∼3.5 ×lower noise than the maps used in this analysis.
 Publication:

Physical Review D
 Pub Date:
 October 2021
 DOI:
 10.1103/PhysRevD.104.083509
 arXiv:
 arXiv:2103.13618
 Bibcode:
 2021PhRvD.104h3509B
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 Submitted to PRD