English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Ground-based optical astronomical observations supported by or in thevicinity of laser guide-star systems can be contaminated by Raman-scatteredlaser photons. Anticipating, alleviating, and correcting for the impact of thisself-inflicted contamination requires a detailed knowledge of thepure-rotational and rotational-vibrational spectrum of the molecules in ouratmosphere. We present a 15.3hr-deep combined spectrum of the 4LGSF's 589nm$\approx$ 509THz sodium laser beams of Paranal observatory, acquired with theESPRESSO spectrograph at a resolution$\lambda/\Delta\lambda\cong140'000\approx0.12$ cm$^{-1}$ and an altitude of 23km above mean sea level. We identify 865 Raman lines over the spectral range of[3770; 7900]{\AA}$\approx$[+9540; -4315] cm$^{-1}$, with relative intensitiesspanning ~5 orders of magnitudes. These lines are associated to the mostabundant molecules of dry air, including their isotopes: 14N14N, 14N15N,16O16O, 16O17O, 16O18O, and 12C16O16O. The signal-to-noise of theseobservations implies that professional observatories can treat the resultingcatalogue of Raman lines as exhaustive (for the detected molecules, over theobserved Raman shift range) for the purpose of predicting/correcting/exploitingRaman lines in astronomical data.  Our observations also reveal that the four laser units of the 4LGSF do notall lase at the same central wavelength. [...] The [measured] offsets [...] arelarger than the observed 4LGSF spectral stability of $\pm$3 MHz over hours.They remain well within the operational requirements for creating artificiallaser guide-stars, but hinder the assessment of the radial velocity accuracy ofESPRESSO at the required level of 10 m/s. Altogether, our observationsdemonstrate how Raman lines can be exploited by professional observatories ashighly-accurate, on-sky wavelength references.

The pure-rotational and rotational-vibrational Raman spectrum of the atmosphere at an altitude of 23 km