Chandra spectra of Si XIV (top panels) compared with GTC spectroscopy in the He I and Hα regions (mid and bottom panels). The right panels are zoomed version of the left ones aimed at highlighting the blue-shifted absorption features. Dotted vertical lines mark the core velocity (−1500 km s⁻¹) of the He I absorption component, while the dotted-dashed vertical lines mark (approximately) its blue-edge velocity (blue; −3000 km s⁻¹) and the corresponding receding velocity (red; 3000 km s⁻¹).