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Adaptive optics with an infrared pyramid wavefront sensor at Keck

Bond, Charlotte Z. and Cetre, Sylvain and Lilley, Scott and Wizinowich, Peter and Mawet, Dimitri and Chun, Mark and Wetherell, Edward and Jacobson, Shane and Lockhart, Charles and Warmbier, Eric and Ragland, Sam and Alvarez, Carlos and Guyon, Olivier and Goebel, Sean and Delorme, Jacques-Robert and Jovanovic, Nemanja and Hall, Donald N. and Wallace, James K. and Taheri, Mojtaba and Plantet, Cedric and Chambouleyron, Vincent (2020) Adaptive optics with an infrared pyramid wavefront sensor at Keck. Journal of Astronomical Telescopes, Instruments, and Systems, 6 (3). Art. No. 039003. ISSN 2329-4124. doi:10.1117/1.JATIS.6.3.039003.

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The study of cold or obscured, red astrophysical sources can significantly benefit from adaptive optics (AO) systems employing infrared (IR) wavefront sensors. One particular area is the study of exoplanets around M-dwarf stars and planet formation within protoplanetary disks in star-forming regions. Such objects are faint at visible wavelengths but bright enough in the IR to be used as a natural guide star for the AO system. Doing the wavefront sensing at IR wavelengths enables high-resolution AO correction for such science cases, with the potential to reach the contrasts required for direct imaging of exoplanets. To this end, a new near-infrared pyramid wavefront sensor (PyWFS) has been added to the Keck II AO system, extending the performance of the facility AO system for the study of faint red objects. We present the Keck II PyWFS, which represents a number of firsts, including the first PyWFS installed on a segmented telescope and the first use of an IR PyWFS on a 10-m class telescope. We discuss the scientific and technological advantages offered by IR wavefront sensing and present the design and commissioning of the Keck PyWFS. In particular, we report on the performance of the Selex Avalanche Photodiode for HgCdTe InfraRed Array detector used for the PyWFS and highlight the novelty of this wavefront sensor in terms of the performance for faint red objects and the improvement in contrast. The system has been commissioned for science with the vortex coronagraph in the NIRC2 IR science instrument and is being commissioned alongside a new fiber injection unit for NIRSPEC. We present the first science verification of the system—to facilitate the study of exoplanets around M-type stars.

Item Type:Article
Related URLs:
URLURL TypeDescription
Wizinowich, Peter0000-0002-1646-442X
Mawet, Dimitri0000-0002-8895-4735
Guyon, Olivier0000-0002-1097-9908
Goebel, Sean0000-0003-3763-2418
Jovanovic, Nemanja0000-0001-5213-6207
Additional Information:© 2020 The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Received: 23 March 2020; Accepted: 27 August 2020; Published: 24 September 2020. The near-infrared pyramid wavefront sensor is supported by the National Science Foundation under Grant No. AST-1611623. The camera used with the pyramid wavefront sensor is provided by Don Hall with support by the National Science Foundation under Grant No. AST-1106391. The FIU is supported by the Heising-Simons Foundation. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Group:Astronomy Department
Funding AgencyGrant Number
Heising-Simons FoundationUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:adaptive optics; astronomy; wavefront sensing; infrared
Issue or Number:3
Record Number:CaltechAUTHORS:20201008-100949118
Persistent URL:
Official Citation:Charlotte Z. Bond, Sylvain Cetre, Scott Lilley, Peter Wizinowich, Dimitri Mawet, Mark Chun, Edward Wetherell, Shane Jacobson, Charles Lockhart, Eric Warmbier, Sam Ragland, Carlos Álvarez, Olivier Guyon, Sean Goebel, Jacques-Robert Delorme, Nemanja Jovanovic, Donald N. Hall, James K. Wallace, Mojtaba Taheri, Cedric Plantet, and Vincent Chambouleyron "Adaptive optics with an infrared pyramid wavefront sensor at Keck," Journal of Astronomical Telescopes, Instruments, and Systems 6(3), 039003 (24 September 2020).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105919
Deposited By: Tony Diaz
Deposited On:08 Oct 2020 17:28
Last Modified:16 Nov 2021 18:47

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