5–7 nov. 2025
Université de Montpellier
Fuseau horaire Europe/Paris

SPT-3G D1: CMB temperature and polarization power spectra and cosmology from 2019 and 2020 observations of the SPT-3G Main field

7 nov. 2025, 11:30
40m
Amphithéâtre de physique, bâtiment 20 (Université de Montpellier)

Amphithéâtre de physique, bâtiment 20

Université de Montpellier

Université de Montpellier, campus Triolet Parvis Alexander Grothendieck 34095 Montpellier Zoom link: https://umontpellier-fr.zoom.us/j/5653271803?pwd=bVRSTi9wMW9BTkE0WDEyalFEQlVIdz09

Orateur

Etienne Camphuis

Description

I will present the most precise measurements of CMB temperature and polarization power spectra from SPT-3G observations of 4% of the sky during 2019-2020. Using the deepest CMB maps to date for a TT/TE/EE analysis, we achieve the most precise measurements of the lensed EE and TE spectra at small angular scales. These results provide strong confirmation of the ΛCDM model and yield cosmological constraints comparable to Planck. From SPT-3G alone, we measure H₀=66.66±0.60 km/s/Mpc, confirming the Hubble tension at 6.2σ significance relative to SH0ES.
For the first time, combined ground-based CMB experiments (SPT+ACT) reach Planck's constraining power on key parameters. The combination of all three CMB experiments yields the tightest constraints to date: H₀=67.24±0.35 km/s/Mpc and σ₈=0.8137±0.0038. While CMB data alone show no evidence for physics beyond ΛCDM, we observe a growing 2.8σ discrepancy with DESI BAO results, which drives 2-3σ deviations from the standard model when combined.

Documents de présentation

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