The Keck Cosmic Web Imager Integral Field Spectrograph
Abstract
We report on the design and performance of the Keck Cosmic Web Imager (KCWI), a general purpose optical integral field spectrograph that has been installed at the Nasmyth port of the 10 m Keck II telescope on Maunakea, Hawaii. The novel design provides blue-optimized seeing-limited imaging from 350–560 nm with configurable spectral resolution from 1000–20,000 in a field of view up to 20'' × 33''. Selectable volume phase holographic (VPH) gratings and high-performance dielectric, multilayer silver, and enhanced-aluminum coatings provide end-to-end peak efficiency in excess of 45% while accommodating the future addition of a red channel that will extend wavelength coverage to 1 micron. KCWI takes full advantage of the excellent seeing and dark sky above Maunakea with an available nod-and-shuffle observing mode. The instrument is optimized for observations of faint, diffuse objects such as the intergalactic medium or cosmic web. In this paper, a detailed description of the instrument design is provided with measured performance results from the laboratory test program and 10 nights of on-sky commissioning during the spring of 2017. The KCWI team is lead by Caltech and JPL (project management, design, and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (observatory interfaces).
Additional Information
© 2018 The American Astronomical Society. Received 2018 February 20; revised 2018 July 4; accepted 2018 July 12; published 2018 September 4. The Keck Cosmic Web Imager was developed through a collaboration of the California Institute of Technology, the University of California, and the W. M. Keck Observatory. The research described in this publication was carried out by the California Institute of Technology and by the Jet Propulsion Laboratory, which is managed by the California Institute of Technology. The work was sponsored by grants from the Telescope System Instrumentation Program (TSIP) and the Major Research Instrumentation Program (MRI) of the National Science Foundation, as well as grants from the Heising-Simons Foundation, the W. M. Keck Observatory, and the Caltech Division of Physics, Math and Astronomy. We acknowledge our major industrial partner Winlight Optics (Pertuis, France) for their cooperation and assistance in the fabrication of the IFU and powered reflective optics. We would also like to thank the referee for constructive and helpful comments. Much of the data presented herein were obtained at the W. M. Keck Observatory, which 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. Facilities: GALEX - Galaxy Evolution Explorer satellite, Hale - , Keck:II (KCWI) - , Spitzer. -Attached Files
Published - Morrissey_2018_ApJ_864_93.pdf
Accepted Version - 1807.10356.pdf
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Additional details
- Eprint ID
- 89357
- Resolver ID
- CaltechAUTHORS:20180904-103955908
- NSF
- Heising-Simons Foundation
- W. M. Keck Foundation
- Caltech
- Created
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2018-09-04Created from EPrint's datestamp field
- Updated
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2023-03-16Created from EPrint's last_modified field
- Caltech groups
- Space Astrophysics Laboratory