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Proceedings Paper

Suppressing speckle noise for simultaneous differential extrasolar planet imaging (SDI) at the VLT and MMT
Author(s): Beth A. Biller; Laird Close; Rainer Lenzen; Wolfgang Brandner; Donald W. McCarthy; Eric Nielsen; Markus Hartung
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Paper Abstract

We discuss data reduction techniques and results from the Simultaneous Differential Imager (SDI) implemented at the VLT (Lenzen et al. 2004a) and the MMT. SDI uses a quad filter to take images simultaneously at 3 wavelengths surrounding the 1.62 μm methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in these filters, speckle noise from the primary can be attenuated by a factor of >102. Non-trivial data reduction tools are necessary to pipeline the simultaneous differential imaging. Here we discuss a custom algorithm implemented in IDL to perform this reduction. The script performs basic data reduction tasks but also precisely aligns images taken in each of the filters using a custom shift and subtract routine. In our commissioning runs at the VLT and MMT, we achieved contrasts up to a factor of 45000 (ΔH=11.7) at a separation of 0.6" from the primary star. With this degree of attenuation, we should be able to image a 2-4 Jupiter mass planet at 5 AU around a 30 Myr star at 10 pc. We believe that our SDI images are the highest contrast astronomical images ever made from ground or space.

Paper Details

Date Published: 25 October 2004
PDF: 9 pages
Proc. SPIE 5490, Advancements in Adaptive Optics, (25 October 2004); doi: 10.1117/12.552164
Show Author Affiliations
Beth A. Biller, Steward Observatory/Univ. of Arizona (United States)
Laird Close, Steward Observatory/Univ. of Arizona (United States)
Rainer Lenzen, Max-Planck-Institut für Astronomie (Germany)
Wolfgang Brandner, Max-Planck-Institut für Astronomie (Germany)
Donald W. McCarthy, Steward Observatory/Univ. of Arizona (United States)
Eric Nielsen, Steward Observatory/Univ. of Arizona (United States)
Markus Hartung, European Southern Observatory (Chile)

Published in SPIE Proceedings Vol. 5490:
Advancements in Adaptive Optics
Domenico Bonaccini Calia; Brent L. Ellerbroek; Roberto Ragazzoni, Editor(s)

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