Wavelength regions centered at the five selected magnesium lines for the thin-disk star 2M17584888-2351011 (star 40; top row panels) and the thick-disk star 2M18522108-3022143 (star 44; bottom row panels). The panels in each row are arranged in increasing order of the wavelengths of the selected lines. In each panel, the black circles denote the observed spectrum, the crimson line denotes the best-fit synthetic spectrum, and the red band denotes the variation in the synthetic spectrum for a difference of ±0.2 dex in the [Mg/Fe]. The yellow bands in each panel represent the line masks defined for the Mg lines, wherein SME fits observed spectra by varying the magnesium abundance and finds the best synthetic spectra fit by ξ² minimization. The green line shows the synthetic spectrum without Mg, also indicating any possible blends in the line. The [Mg/Fe] values corresponding to the best-fit case for each Mg line are listed in each panel. All identified atomic and molecular lines are also denoted in the top part of the top row panels.