KAPA: A new Keck laser-guide star AO system that increases image quality and sky coverage

Many notable discoveries have been made with the world's largest telescopes equipped with adaptive optics (AO) to overcome the blurring effects of the Earth's turbulent atmosphere and deliver diffraction-limited resolution. Still, laser-guide star (LGS) AO has not achieved its full potential due to several key factors: (a) only sampling an incomplete "cone" of atmospheric turbulence (with a single LGS), (b) limited sky coverage due to the continued need for at least one optical natural guide star, and (c) poor knowledge of the point spread function (PSF) delivered by the AO systems, which is critical for extracting quantitative information from our astronomical observations. W. M. Keck Observatory is upgrading the Keck I LGS AO system in a project entitled "Keck All Sky Precision Adaptive Optics (KAPA)". KAPA's distinctive advantage is the new combination of excellent AO correction (high Strehl ratios) over a very large fraction of the sky accompanied by accurate PSF estimates. KAPA will enable a broad range of science cases. The four key KAPA science cases are (1) constraining dark matter, the Hubble constant, and dark energy using strong gravitational lenses, (2) testing general relativity and supermassive black hole interactions at the Galactic center, (3) characterizing galaxy kinematics and metallicity using rare highly magnified galaxies, and (4) directly studying gas-giant protoplanets around the youngest stars. We will present KAPA capabilities that are coming on sky starting in 2020 and culminate in first-light in 2024. We will also present KAPA performance predictions and public data products and science impact from the four key science surveys.