An H-band Vector Vortex Coronagraph for the Subaru Coronagraphic Extreme-adaptive Optics System
Abstract
The vector vortex is a coronagraphic imaging mode of the recently commissioned Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) platform on the 8 m Subaru Telescope. This multi-purpose high-contrast visible and near-infrared (R- to K-band) instrument is not only intended to serve as a VLT-class “planet-imager” instrument in the northern hemisphere, but also to operate as a technology demonstration testbed ahead of the ELTs-era, with a particular emphasis on small inner-working angle (IWA) coronagraphic capabilities. The given priority to small-IWA imaging led to the early design choice to incorporate focal-plane phase-mask coronagraphs. In this context, a test H-band vector vortex liquid crystal polymer waveplate was provided to SCExAO, to allow a one-to-one comparison of different small-IWA techniques on the same telescope instrument, before considering further steps. Here we present a detailed overview of the vector vortex coronagraph, from its installation and performances on the SCExAO optical bench, to the on-sky results in the extreme AO regime, as of late 2016/early 2017. To this purpose, we also provide a few recent on-sky imaging examples, notably high-contrast ADI detection of the planetary-mass companion κ Andromedae b, with a signal-to-noise ratio above 100 reached in less than 10 mn exposure time.
- Publication:
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Publications of the Astronomical Society of the Pacific
- Pub Date:
- March 2018
- DOI:
- 10.1088/1538-3873/aa9fe5
- arXiv:
- arXiv:1712.02040
- Bibcode:
- 2018PASP..130c5001K
- Keywords:
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- Astrophysics - Instrumentation and Methods for Astrophysics;
- Physics - Instrumentation and Detectors
- E-Print:
- 25 pages, 8 figures, accepted for publication in Publications of the Astronomical Society of the Pacific (PASP)