26 July 2016 Commissioning and first light results of an L'-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument
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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.
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Bruno Femenía Castellá, Bruno Femenía Castellá, Eugene Serabyn, Eugene Serabyn, Dimitri Mawet, Dimitri Mawet, Olivier Absil, Olivier Absil, Peter Wizinowich, Peter Wizinowich, Keith Matthews, Keith Matthews, Elsa Huby, Elsa Huby, Michael Bottom, Michael Bottom, Randy Campbell, Randy Campbell, Dwight Chan, Dwight Chan, Brunella Carlomagno, Brunella Carlomagno, Sylvain Cetre, Sylvain Cetre, Denis Defrère, Denis Defrère, Christian Delacroix, Christian Delacroix, Carlos Gomez Gonzalez, Carlos Gomez Gonzalez, Aïssa Jolivet, Aïssa Jolivet, Mikael Karlsson, Mikael Karlsson, Kyle Lanclos, Kyle Lanclos, Scott Lilley, Scott Lilley, Steven Milner, Steven Milner, Henry Ngo, Henry Ngo, Maddalena Reggiani, Maddalena Reggiani, Julia Simmons, Julia Simmons, Hien Tran, Hien Tran, Ernesto Vargas Catalan, Ernesto Vargas Catalan, Olivier Wertz, Olivier Wertz, "Commissioning and first light results of an L'-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument", Proc. SPIE 9909, Adaptive Optics Systems V, 990922 (26 July 2016); doi: 10.1117/12.2233228; https://doi.org/10.1117/12.2233228
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