First Faint Dual-field Off-axis Observations in Optical Long Baseline Interferometry
Abstract
Ground-based long baseline interferometers have long been limited in sensitivity in part by the short integration periods imposed by atmospheric turbulence. The first observation fainter than this limit was performed on 2011 January 22 when the Keck Interferometer observed a K = 11.5 target, about 1 mag fainter than its K = 10.3 atmospherically imposed limit; the currently demonstrated limit is K = 12.5. These observations were made possible by the Dual-Field Phase-Referencing (DFPR) instrument, part of the NSF-funded ASTrometry and phase-Referenced Astronomy project; integration times longer than the turbulence time scale are made possible by its ability to simultaneously measure the real-time effects of the atmosphere on a nearby bright guide star and correct for it on the faint target. We present the implementation of DFPR on the Keck Interferometer. Then, we detail its on-sky performance focusing on the accuracy of the turbulence correction and the resulting fringe contrast stability.
Additional Information
© 2014 American Astronomical Society. Received 2013 July 19; accepted 2014 January 24; published 2014 February 20. The ASTRA project was supported by the National Science Foundation Major Research Instrumentation grant AST-0619965. The Keck Interferometer was funded by the National Aeronautics and Space Administration as part of its Exoplanet Exploration program. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.Attached Files
Published - 0004-637X_783_2_104.pdf
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Additional details
- Eprint ID
- 46308
- Resolver ID
- CaltechAUTHORS:20140617-131022855
- AST-0619965
- NSF
- NASA
- Created
-
2014-06-17Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)