New windows in the submillimeter sky with the CCAT Observatory

The CCAT Observatory is building the Fred Young Submillimeter Telescope, a novel, high-throughput, 6-meter aperture telescope, to enable a wide range of new measurements. The science goals include line-intensity mapping of cosmic reionization, studying galaxy clusters, galactic magnetic fields, astronomical transients, and others. The Observatory is under construction at 5600 meters on Cerro Chajnantor, Chile. We highlight the complementarity of CCAT and current Cosmic Microwave Background surveys and describe CCAT's submillimeter measurement capabilities with its first high-throughput science receiver: Prime-Cam. This camera is designed to support over 100,000 kinetic inductance detectors and enable over 10x faster mapping speed than previous submillimeter observatories in windows from 0.3 – 1.1 mm (280 – 850 GHz). We present the astrophysics and cosmology science goals, the project status, and plans for early science observations starting in 2026.