Broadband near-infrared astronomical spectrometer calibration and on-sky validation with an electro-optic laser frequency comb
Journal
Date Issued
2018
Author(s)
Obrzud, E.
•
•
Harutyunyan, A.
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Chazelas, B.
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Cecconi, M.
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Ghedina, A.
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•
Kundermann, S.
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Lecomte, S.
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Pepe, F.
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Wildi, F.
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Bouchy, F.
•
Herr, T.
Abstract
The quest for extrasolar planets and their characterisation as well as studies of fundamental physics on cosmological scales rely on capabilities of high-resolution astronomical spectroscopy. A central requirement is a precise wavelength calibration of astronomical spectrographs allowing for extraction of subtle wavelength shifts from the spectra of stars and quasars. Here, we present an all-fibre, 400 nm wide near-infrared frequency comb based on electro-optic modulation with 14.5 GHz comb line spacing. Tests on the high-resolution, near-infrared spectrometer GIANO-B show a photon-noise limited calibration precision of <10 cm/s as required for Earth-like planet detection. Moreover, the presented comb provides detailed insight into particularities of the spectrograph such as detector inhomogeneities and differential spectrograph drifts. The system is validated in on-sky observations of a radial velocity standard star (HD221354) and telluric atmospheric absorption features. The advantages of the system include simplicity, robustness and turn-key operation, features that are valuable at the observation sites.
Volume
26
Issue
26
Start page
34830
Issn Identifier
1094-4087
Ads BibCode
2018OExpr..2634830O
Rights
open.access
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