M. El Morsy
Validation of strategies for coupling exoplanet PSFs into single-mode fibres for high-dispersion coronagraphy
El Morsy, M.; Vigan, A.; Lopez, M.; Otten, G.P.P.L.; Choquet, E.; Madec, F.; Costille, A.; Sauvage, J.-F.; Dohlen, K.; Muslimov, E.; Pourcelot, R.; Floriot, J.; Benedetti, J.-A.; Blanchard, P.; Balard, P.; Murray, G.
Mr Graham Murray email@example.com
Senior Research Fellow
On large ground-based telescopes, the combination of extreme adaptive optics (ExAO) and coronagraphy with high-dispersion spectroscopy (HDS), sometimes referred to as high-dispersion coronagraphy (HDC), is starting to emerge as a powerful technique for the direct characterisation of giant exoplanets. The high spectral resolution not only brings a major gain in terms of accessible spectral features, but also enables a better separation of the stellar and planetary signals. Ongoing projects such as Keck/KPIC, Subaru/REACH, and VLT/HiRISE base their observing strategy on the use of a few science fibres, one of which is dedicated to sampling the planetŠs signal, while the others sample the residual starlight in the speckle field. The main challenge in this approach is to blindly centre the planet’s point spread function (PSF) accurately on the science fibre, with an accuracy of less than 0.1 λ/D to maximise the coupling efficiency. In the context of the HiRISE project, three possible centring strategies are foreseen, either based on retro-injecting calibration fibres to localise the position of the science fibre or based on a dedicated centring fibre. We implemented these three approaches, and we compared their centring accuracy using an upgraded setup of the MITHiC high-contrast imaging testbed, which is similar to the setup that will be adopted in HiRISE. Our results demonstrate that reaching a specification accuracy of 0.1 λ/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We studied the contributors to the centring error in the case of MITHiC and we propose a quantification for some of the most impacting terms.
El Morsy, M., Vigan, A., Lopez, M., Otten, G., Choquet, E., Madec, F., …Murray, G. (2022). Validation of strategies for coupling exoplanet PSFs into single-mode fibres for high-dispersion coronagraphy. Astronomy & Astrophysics, 667, Article A171. https://doi.org/10.1051/0004-6361/202243408
|Journal Article Type||Article|
|Acceptance Date||May 9, 2022|
|Online Publication Date||Nov 25, 2022|
|Deposit Date||Mar 6, 2023|
|Publicly Available Date||Mar 6, 2023|
|Journal||Astronomy & Astrophysics|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
Publisher Licence URL
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0),<br /> which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.<br /> This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication.
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