A legacy of GES: The INTRIGOSS library of Hi-Res synthetic spectra for FGK stars

INTRIGOSS (INaf-TRIeste Grid Of Synthetic Spectra) is a High-Resolution (Hi-Res) synthetic spectra library designed for studying FGK stars. The library was created by taking advantage of the UVESU580 spectra of stars from the Gaia–ESO survey (GES), their atmospheric parameters, and abundances derived by the GES consortium to assess its validity.

The library is based on atmosphere models computed with ATLAS12 code which allows us to specify individual element abundances in deriving stellar atmosphere structures. The synthetic spectra, both Normalized SPectra (NSPs) and surface Flux Spectra (FSPs), in the wavelength range 4830–5400 A were computed in a fully consistent mode using the SPECTRUM code.

A new line list was built by merging the line data used by Lobel (2011) with a line list provided to us by R. O. Gray (2011, private communication), complemented with molecular lines of CH, NH, MgH, SiH,C2 , CN, and TiO and with both atomic (in the three main expected stages of ionization) and molecular Predicted Lines (PLs) from Kurucz's site. The list was optimized by tuning as many oscillator strengths as possible in order to reproduce a set of Hi-Res reference spectra, i.e. a solar spectrum (S/N~4000) and the Gaia-ESO UVES spectra of five cool giants.

The greater accuracy of INTRIGOSS NSPs with respect to the spectra from other synthetic libraries (e.g., Coelho et al. 2005, C05; de Laverny et al. 2012, AMBRE; Husser et al. 2013, PHOENIX; Coelho 2014, C14; Brahm et al. 2017, B17) is shown. The good agreement between observational and synthetic Lick/SDSS indices shows that the predicted blanketing of INTRIGOSS FSPs well reproduces the observed one, thus confirming the reliability of INTRIGOSS surface flux spectra.

The library is available on line (http://archives.ia2.inaf.it/intrigoss/) and uses the facilities of the Italian Center for Astronomical Archive (IA2) operated by INAF.