Physics Research Conference

In the 50+ years since its discovery, the cosmic microwave background (CMB) has yielded surprisingly detailed and precise information about the form, content and dynamics of the early universe. High angular resolution maps, and polarization data at all angular scales, are the focus of current and next-generation instruments. The Atacama Cosmology Telescope (ACT) is producing maps of the intensity and polarization of nearly half the sky at arcminute resolution in three frequency bands so far. I will describe the instrument, its high-dynamic-range maps, and the sweep of cosmological and astrophysical questions those maps have been and will be used to address. I will also give a quick description of a new suite of instruments comprising the Simons Observatory, including context to the emerging CMB-S4 program.