First faint dual-field off-axis observations in optical long baseline interferometry
- W. M. Keck Observatory, Kamuela, HI 96743 (United States)
- NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States)
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
- University of Arizona, Tucson, AZ 85721-0065 (United States)
- University of Michigan, Ann Arbor, MI 48109-1090 (United States)
- Max-Planck-Institut für Astronomie, Heidelberg, D-69117 (Germany)
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.
- OSTI ID:
- 22351585
- Journal Information:
- Astrophysical Journal, Vol. 783, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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