L'-band AGPM vector vortex coronagraph's first light on VLT/NACO: Discovery of a late-type companion at two beamwidths from an F0V star
Abstract
Context. High contrast imaging has thoroughly combed through the limited search space accessible with first-generation ground-based adaptive optics instruments and the Hubble Space Telescope. Only a few objects were discovered, and many non-detections reported and statistically interpreted. The field is now in need of a technological breakthrough. Aims. Our aim is to open a new search space with first-generation systems such as NACO at the Very Large Telescope, by providing ground-breaking inner working angle (IWA) capabilities in the L′ band. The L′ band is a sweet spot for high contrast coronagraphy since the planet-to-star brightness ratio is favorable, while the Strehl ratio is naturally higher. Methods. An annular groove phase mask (AGPM) vector vortex coronagraph optimized for the L′ band made from diamond subwavelength gratings was manufactured and qualified in the lab. The AGPM enables high contrast imaging at very small IWA, potentially being the key to unexplored discovery space. Results. Here we present the installation and successful on-sky tests of an L'-band AGPM coronagraph on NACO. Using angular differential imaging, which is well suited to the rotational symmetry of the AGPM, we demonstrated a ΔL′ > 7.5 mag contrast from an IWA ≃ 0."09 onwards, during average seeing conditions, and for total integration times of a few hundred seconds.
Additional Information
© 2013 ESO. Received 18 February 2013; Accepted 1 April 2013. This work was carried out at the European Southern Observatory (ESO) site of Vitacura (Santiago, Chile). O.A. and J.S. acknowledge support from the Communauté française de Belgique – Actions de recherché concertées – Académie universitaire Wallonie-Europe. We would like to thank the referee, Dr Christian Marois, for his constructive comments.Attached Files
Published - aa21315-13.pdf
Submitted - 1304.0930v1.pdf
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Additional details
- Eprint ID
- 57711
- Resolver ID
- CaltechAUTHORS:20150520-115106627
- Communauté française de Belgique – Actions de recherche concertées – Académie universitaire Wallonie-Europe
- Created
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2015-05-20Created from EPrint's datestamp field
- Updated
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2023-03-16Created from EPrint's last_modified field