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Proceedings Paper

Commissioning and first light results of an L'-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument
Author(s): Bruno Femenía Castellá; Eugene Serabyn; Dimitri Mawet; Olivier Absil; Peter Wizinowich; Keith Matthews; Elsa Huby; Michael Bottom; Randy Campbell; Dwight Chan; Brunella Carlomagno; Sylvain Cetre; Denis Defrère; Christian Delacroix; Carlos Gomez Gonzalez; Aïssa Jolivet; Mikael Karlsson; Kyle Lanclos; Scott Lilley; Steven Milner; Henry Ngo; Maddalena Reggiani; Julia Simmons; Hien Tran; Ernesto Vargas Catalan; Olivier Wertz
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Paper Abstract

On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7μm. We describe the hardware installation of the vortex phase mask during a routine NIRC2 service mission. The success of the project depends on extensive software development which has allowed the achievement of exquisite real-time pointing control as well as further contrast improvements by using speckle nulling to mitigate the effect of static speckles. First light of the new coronagraphic mode was on June 2015 with already very good initial results. Subsequent commissioning nights were interlaced with science nights by members of the VORTEX team with their respective scientific programs. The new capability and excellent results so far have motivated the VORTEX team and the Keck Science Steering Committee (KSSC) to offer the new mode in shared risk mode for 2016B.

Paper Details

Date Published: 26 July 2016
PDF: 14 pages
Proc. SPIE 9909, Adaptive Optics Systems V, 990922 (26 July 2016); doi: 10.1117/12.2233228
Show Author Affiliations
Bruno Femenía Castellá, W. M. Keck Observatory (United States)
Eugene Serabyn, Jet Propulsion Lab. (United States)
Dimitri Mawet, California Institute of Technology (United States)
Olivier Absil, Univ. of Liège (Belgium)
Peter Wizinowich, W. M. Keck Observatory (United States)
Keith Matthews, California Institute of Technology (United States)
Elsa Huby, Univ. of Liège (Belgium)
Michael Bottom, California Institute of Technology (United States)
Randy Campbell, W. M. Keck Observatory (United States)
Dwight Chan, W. M. Keck Observatory (United States)
Brunella Carlomagno, Univ. of Liège (Belgium)
Sylvain Cetre, W. M. Keck Observatory (United States)
Denis Defrère, Univ. of Arizona (United States)
Christian Delacroix, Cornell Univ. (United States)
Carlos Gomez Gonzalez, Univ. of Liège (Belgium)
Aïssa Jolivet, Univ. of Liège (Belgium)
Mikael Karlsson, Uppsala Univ. (Sweden)
Kyle Lanclos, W. M. Keck Observatory (United States)
Scott Lilley, W. M. Keck Observatory (United States)
Steven Milner, W. M. Keck Observatory (United States)
Henry Ngo, California Institute of Technology (United States)
Maddalena Reggiani, Univ. of Liège (Belgium)
Julia Simmons, W. M. Keck Observatory (United States)
Hien Tran, W. M. Keck Observatory (United States)
Ernesto Vargas Catalan, Uppsala Univ. (Sweden)
Olivier Wertz, Univ. of Liège (Belgium)

Published in SPIE Proceedings Vol. 9909:
Adaptive Optics Systems V
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)

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