Spectrum of the diffuse emission extracted from the black rectangle in Fig. 3 (called “bright”) minus the emission from the red rectangle (“dim”). The black line shows the best-fit model, while the dotted lines show the two best fit hot plasma components. At energies higher than ∼1 keV the difference spectrum shows a rapidly decreasing spectrum. The plot, in logarithmic scale shows only the fraction of energy bins with positive values, while the negative values are not displayed. Consequently, at high energies the data displayed are biased high, while the model properly accounts for both positive and negative energy bins.