Rotational and rotational-vibrational Raman spectroscopy of air to characterize astronomical spectrographs

Abstract

Raman scattering enables unforeseen uses for the laser guide-star system of the Very Large Telescope. Here, we present the observation of one up-link sodium laser beam acquired with the ESPRESSO spectrograph at a resolution $\lambda /\Delta \lambda \sim 140^{\prime }000$. In 900s on-source, we detect the pure rotational Raman lines of ${}^{16}$O${}_2$, ${}^{14}$N${}_2$, and ${}^{14}$N${}^{15}$N (tentatively) up to rotational quantum numbers $J$ of 27, 24, and 9, respectively. We detect the ${}^{16}$O${}_2$ fine-structure lines induced by the interaction of the electronic spin \textbf{S} and end-over-end rotational angular momentum \textbf{N} in the electronic ground state of this molecule up to $N=9$. The same spectrum also reveals the ${\nu }_{1\leftarrow 0}$ rotational-vibrational Q-branch for ${}^{16}$O${}_2$ and ${}^{14}$N${}_2$. These observations demonstrate the potential of using laser guide-star systems as accurate calibration sources for characterizing new astronomical spectrographs.

arXiv comment11 pages, 3 figures. Accepted for publication in Physical Review Letters

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Cited by in corpus (6)

• The Data Processing Pipeline for the MUSE Instrument
• A Spectral Survey of WASP-19b with ESPRESSO
• Fundamental physics with Espresso: Towards an accurate wavelength calibration for a precision test of the fine-structure constant
• A Precise Photometric Ratio via Laser Excitation of the Sodium Layer I: One-photon Excitation Using 342.78 nm Light
• Revisiting the Emission Line Source Detection Problem in Integral Field Spectroscopic Data
• Laser Guide Star uplink beam: scattering and Raman emission measurements with the 10.4m Gran Telescopio CANARIAS