Non-local Thermodynamic Equilibrium Stellar Spectroscopy with 1D and 3D Models. II. Chemical Properties of the Galactic Metal-poor Disk and the Halo
From exploratory studies and theoretical expectations it is known that simplifying approximations in spectroscopic analysis (local thermodynamic equilibrium (LTE), 1D) lead to systematic biases of stellar parameters and abundances. These biases depend strongly on surface gravity, temperature and, in particular, for LTE versus non-LTE (NLTE), on metallicity of the stars. Here we analyze the [Mg/Fe]