The Keck Wide-Field Imager: Optical partner to Roman
The Keck Wide-Field Imager (KWFI) is a 1 degree diameter field of view imager for the Keck telescopes that will be the most powerful wide-field optical imager on Earth or in space for the foreseeable future. KWFI has extreme optical throughput to 10000A and maintains that high sensitivity down to 3000A to enable new science for decades that cannot be done on any other telescope, not even 30m-class telescopes. Such a powerful wide-field imager, with fast filter change, broad and narrowband imaging, target-of-opportunity capability, and a multiplexing mode for rapid deep Keck spectroscopy will progress nearly every area of astronomy, including cosmic reionization and high-redshift galaxies, dark matter and dark energy surveys, low-redshift galaxies and the Milky Way, low surface brightness galaxies, features, and sources, stellar populations and formation, exoplanets and the solar system, and time domain science at all wavelengths/energies, particles, and gravitational waves. For Roman, KWFI will provide deep (mag ~ 28-30) 3000-7000A wide-field imaging (e.g., for accurate photometric redshifts, z ~ 2-4 drop-out galaxy selection, supernova classification) and other capabilities that will be very important for its main science goals, along with many other user science cases. I will discuss the status of KWFI, its continued progress, and the development of a deployable secondary mirror to enable new science via deep, wide-field fast imaging and spectroscopic capability within minutes.