First faint dual-field phase-referenced observations on the Keck interferometer
Abstract
Ground-based long baseline interferometers have long been limited in sensitivity by the short integration periods imposed by atmospheric turbulence. The first observation fainter than this limit was performed on January 22, 2011 when the Keck Interferometer observed a K=11.5 target, about one magnitude fainter than its K=10.3 limit. This observation was made possible by the Dual Field Phase Referencing instrument of the ASTRA project: simultaneously measuring the real-time effects of the atmosphere on a nearby bright guide star, and correcting for it on the faint target, integration time longer than the turbulence time scale are made possible. As a prelude to this demonstration, we first present the implementation of Dual Field Phase Referencing on the interferometer. We then detail its on-sky performance focusing on the accuracy of the turbulence correction, and on the resulting fringe contrast stability. We conclude with a presentation of early results obtained with Laser Guide Star AO and the interferometer.
Keywords
Cite
@article{arxiv.1207.5019,
title = {First faint dual-field phase-referenced observations on the Keck interferometer},
author = {Julien Woillez and Peter Wizinowich and Rachel Akeson and Mark Colavita and Josh Eisner and Rafael Millan-Gabet and John Monnier and Jorg-Uwe Pott and Sam Ragland and Eric Appleby and Andrew Cooper and Claude Felizardo and Jennifer Herstein and Olivier Martin and Drew Medeiros and Douglas Morrison and Tatyana Panteleeva and Brett Smith and Kellee Summers and Kevin Tsubota and Colette Tyau and Ed Wetherell},
journal= {arXiv preprint arXiv:1207.5019},
year = {2015}
}
Comments
10 pages, 12 figures, Proc. SPIE 2012