O VIII/O VII temperature proxy maps. Contributions from the local hot bubble foreground, the instrumental background, the cosmic X-ray background, and the foreground absorption were removed from the maps before we computed the ratio (see the text and Zheng et al. 2024a for further details). Lower panel: ratio of the narrow-band images centered on the O VIII and O VII emission lines. Upper panel: corresponding temperature under the assumption that the narrow-band energy ranges are dominated by O VII and O VIII lines, produced by collisionally ionized plasma.