Using The Cannon and GALAH DR4 to derive stellar parameters and abundances for Gaia RVS spectra
We have used The Cannon to apply stellar parameters and abundances derived from GALAH data (GALAH iDR4) to Gaia RVS spectra (Gaia DR3). We trained our data model on ~14000 selected targets common to both the surveys, utilising the stellar labels from GALAH. With this model, we are able to consistently predict stellar parameters such as T_eff, log g, [Fe/H], and abundances of several alpha elements for over 800,000 Gaia RVS spectra. Using stars from a sample of open and globular clusters present in the Gaia RVS catalogue, we have validated our metallicity estimates. Finally, for a subset of this sample with predicted log g < 3.5 (i.e., giants) we are able to measure the abundances of several neutron-capture elements, illustrating the potential of this method for reliably determining stellar parameters and abundances – as well as identifying candidate accreted stars – from medium-resolution Gaia RVS spectra, a dataset which, by the end of the Gaia mission, will include spectra of over 30 million stars.
