Overview
- The ACT Collaboration published three JCAP papers detailing DR6 maps, power spectra and likelihoods, and constraints on nonstandard cosmological models.
- ACT’s CMB-based Hubble constant agrees with Planck using both temperature and polarization measurements, sharpening the discrepancy with local-universe estimates.
- Analyses rule out about 30 leading extended-model proposals that aimed to resolve the Hubble tension.
- DR6 delivers higher-resolution polarization maps of the cosmic microwave background than Planck, with overall observational capability matching the satellite’s benchmark.
- With the mission concluded, the collaboration has made the full dataset public to enable independent studies and new approaches to the tension.