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arXiv · 1907.05897

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

F. P. A. Vogt·F. Kerber·A. Mehner·S. Yu·T. Pfrommer·G. Lo Curto·P. Figueira·D. Parraguez·F. A. Pepe·D. Mégevand·M. Riva·P. Di Marcantonio·C. Lovis·M. Amate·P. Molaro·A. Cabral·M. R. Zapatero Osorio
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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 $\lambda/\Delta\lambda \sim 140'000$. 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 $\nu_{1\leftarrow0}$ 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.

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F. P. A. Vogt, F. Kerber, A. Mehner, S. Yu, T. Pfrommer, G. Lo Curto, P. Figueira, D. Parraguez, F. A. Pepe, D. Mégevand, M. Riva, P. Di Marcantonio, C. Lovis, M. Amate, P. Molaro, A. Cabral, M. R. Zapatero Osorio. 2019-07-12. Rotational and rotational-vibrational Raman spectroscopy of air to characterize astronomical spectrographs. https://doi.org/10.1103/physrevlett.123.061101

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