"High-Precision CMB Power Spectra and Cosmological Constraints from the Atacama Cosmology Telescope"
I will present power spectra of the cosmic microwave background (CMB) anisotropies in temperature and polarization, as measured from the new, state-of-the-art Atacama Cosmology Telescope (ACT) Data Release 6 maps. These maps cover nearly half of the sky in bands centered at 98, 150, and 220 GHz, with polarization noise levels three times lower than those of the Planck satellite, and angular resolution roughly five times better. I will describe the model developed to fit these data, including detailed treatment of mm-wave foregrounds, and extensive robustness tests of the full analysis pipeline. I will then present constraints on cosmological parameters derived from the ACT DR6 power spectra, as well as from a combination of ACT and legacy data from Planck. ACT and Planck CMB lensing data and baryon acoustic oscillation data from DESI are also used to break geometric degeneracies. Using these data, I will describe the results of several searches for new physics and tests of foundational assumptions of the cosmological model.
