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Published March 10, 2011 | Published
Journal Article Open

Speckle Suppression with the Project 1640 Integral Field Spectrograph


Project 1640 is a high-contrast imaging instrument recently commissioned at the Palomar observatory. A combination of a coronagraph with an integral-field spectrograph (IFS), Project 1640 is designed to detect and characterize extrasolar planets, brown dwarfs, and circumstellar material orbiting nearby stars. In this paper, we present our data processing techniques for improving upon instrument raw sensitivity via the removal of quasi-static speckles. Our approach utilizes the chromatic image diversity provided by the IFS in combination with the locally optimized combination of images algorithm to suppress the intensity of residual contaminating light in close angular proximity to target stars. We describe the Project 1640 speckle suppression pipeline and demonstrate its ability to detect companions with brightness comparable to and below that of initial speckle intensities using on-sky commissioning data. Our preliminary results indicate that suppression factors of at least one order of magnitude are consistently possible, reaching 5σ contrast levels of 2.1 × 10^(–5) at 1" in the H band in 20 minutes of on-source integration time when non-common-path errors are reasonably well calibrated. These results suggest that near-infrared contrast levels of order ≈10^(–7) at subarcsecond separations will soon be possible for Project 1640 and similarly designed instruments that receive a diffraction-limited beam corrected by adaptive optics systems employing deformable mirrors with high actuator density.

Additional Information

© 2011 American Astronomical Society. Received 2010 September 21; accepted 2010 December 14; published 2011 February 18. We are grateful to the staff at Palomar Observatory for their support. Project 1640 is funded by National Science Foundation Grants AST-0520822, AST-0804417, and AST-0908484. L.P. and S.H. acknowledge support from the Carl Sagan Fellowship Program. This work was performed in part under contract with the California Institute of Technology, funded by the National Aeronautics and Space Administration (NASA), through the Sagan Fellowship Program. A portion of the research presented in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contrast with NASA.

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