GSP-spec line list for the parametrisation of Gaia -RVS stellar spectra
  The Gaia mission is a magnitude-limited whole-sky survey that collects an
impressive quantity of astrometric, spectro-photometric and spectroscopic data.
Among all the on-board instruments, the Radial Velocity Spectrometer (RVS)
produces millions of spectra up to a magnitude of G$_{RVS} \sim 16$. For the
brightest RVS targets, stellar atmospheric parameters and individual chemical
abundances are automatically estimated by the Generalized Stellar Parametriser
- spectroscopy group (GSP-Spec). These data will be published with the third
Gaia Data Release. Some major ingredients of the determination of these stellar
parameters include the atomic and molecular line lists that are adopted to
compute reference synthetic spectra, on which the parametrisation methods rely.
We aim to build such a specific line list optimised for the analysis of RVS
late-type star spectra. Starting from the Gaia-ESO line lists, we first
compared the observed and synthetic spectra of six well-known reference
late-type stars in the wavelength range covered by the RVS instrument. We then
improved the quality of the atomic data for the transitions presenting the
largest mismatches. The new line list is found to produce very high-quality
synthetic spectra for the tested reference stars and has thus been adopted
within GSP-Spec.
