The AMBRE project: A new synthetic grid of high-resolution FGKM stellar spectra. A&A544:A126, DOI 10.1051/0004-6361/201219330, 1205.2270 Decin L, Cox NLJ, Royer P, Van Marle AJ, Vandenbussche

Context. Large grids of synthetic spectra covering a widespread range of stellar parameters are mandatory for different stellar and (extra-)Galactic physics applications. For instance, such large grids can be used for the automatic parametrisation of stellar spectra such as that performed within the AMBRE project for which the main goal is the stellar atmospheric parameters determination for the few hundreds of thousands of archived spectra of four ESO spectrographs. Aims. To fulfil the needs of AMBRE and future similar projects, we have computed a grid of synthetic spectra over the whole optical domain for cool to very cool stars of any luminosity (from dwarfs to supergiants) with metallicities varying from 10−5 to 10 times the solar metallicity, and considering large variations in the chemical content of the α-elements. Methods. For these spectrum computations, new generation MARCS model atmospheres and the Turbospectrum code for radiative transfer have been used. We have also taken into account as complete as possible atomic and molecular linelists and adopted, in the spectral synthesis, the same physical assumptions and input data as in the MARCS models. This allowed us to present a grid with a high consistency between the atmosphere models and the synthetic spectra. Results. A new grid of 16 783 high resolution spectra over the wavelength range 3 000 to 12 000 Å has been computed with a spectral resolution always larger than 150 000. Normalised and absolute flux versions are available over a wide range of stellar atmospheric parameters for stars of FGKM spectral types. The covered parameters are 2 500 K≤Teff≤8 000 K,-0.5≤log(g)≤5.5 de