MRI: Track 2 Development of Infrared Wavefront sensor Adaptive optics ('IWA) enabled Astrophysics

This program implements a near-Infrared Wavefront sensor (‘IWA) for the Keck II telescope adaptive optics (AO) system. AO systems correct atmospheric blurring, allowing ground-based telescopes to achieve images as sharp as telescopes in space. A bright guide star is needed to measure the atmospheric errors, and doing so in the infrared enables lower-mass and dust-obscured stars to be used. ‘IWA enables a broad range of new and unique science, from the detection and characterization of young extra-solar planets to tests of black hole physics. ‘IWA builds on recent successful Keck AO upgrades. These upgrades transform Keck II AO from a 2000s-era general purpose system to a state-of-the-art facility for high-resolution infrared astronomy. It is also the first step towards achieving even sharper images in visible light. The ‘IWA project supports student and postdoctoral training in astronomical instrumentation and mentoring for students using the upgraded system for their research. The image quality, contrast, and sky coverage of the Keck II AO system will be significantly improved by ‘IWA’s infrared wavefront sensing capabilities. ‘IWA includes a high-order pyramid wavefront sensor for AO using bright natural guide stars, a medium-order sensing mode for use with fainter natural guide stars, and a low-order sensing mode to support high sky coverage laser guide star AO. ‘IWA also includes a Zernike wavefront sensor to provide improved primary mirror phasing, benefitting all Keck II AO science programs. These capabilities will double the number of extra-solar planets that can be imaged and characterized using two new science instruments: the mid-infrared coronagraphic integral field spectrograph (SCALES) and the fiber-fed high-resolution spectrograph (HISPEC). ‘IWA will also enable AO observations in visible light with 15 mas angular resolution using the existing ORKID imager. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.