Combined spectroscopic calibration for FGK-dwarfs and GK-giants
Mario J P F G Monteiro (Instituto de Astrofisica e Ciencias do Espaço, U.Porto & DFA/FCUP), G. D. C. Teixeira (IA & FCUP, Universidade do Porto), S. A. G. Sousa (IA, Universidade do Porto), N. C. Santos (IA & FCUP, Universidade do Porto), et al.

We use spectra from a joint sample of 708 stars, compiled from 451 FGK-dwarfs and 257 GK-giant stars. We used homogeneously determined spectroscopic stellar parameters to derive temperature calibrations using a set of selected EW line-ratios, and [Fe/H] calibrations using a set of selected FeI lines. We have derived 322 EW line-ratios and 100 FeI lines that can be used to compute Teff and [Fe/H], respectively. These calibrations are shown to be effective, simultaneously, for FGK-dwarfs and GK-giant stars in the following ranges: 4500 K < Teff < 6500 K , 2.5 < logg < 4.9 dex, -0.8 < [Fe/H] < 0.5 dex. The new calibration has a standard deviation of 74 K for Teff and 0.07 dex for [Fe/H]. Four independent samples of stars are used to test and verify the new calibration: a sample of 56 giant stars, a sample composed of GAIA FGK benchmark stars, a sample of 36 GK giant stars of the DR1 of the GAIA-ESO survey, and a sample of 582 FGK dwarfs stars. We also provide a new computer code, GeTCal, to automatically produce new calibration files based on any new sample of stars.