Magnesium region in low (blue, upper two panels) and high (black, lower panel) spectra, corresponding to high and low absorption, respectively. The panels show combined HEG and MEG ±1 order spectra normalized to their respective power-law continua. The solid red line shows the best model fit to the data. Two models for the high-absorption data are shown that differ in their treatment of absorption lines: five individual lines with independent Doppler shifts (upper panel) and a template consisting of Mg xi to iv Kα, all with the same Doppler shift (lower panels). We further show the reference positions of Mg xi to iv Kα (Behar & Netzer 2002) as well as for the H-like Mg xii Lyα and He-like Mg xi triplet lines.