Left panel: X-ray spectrum of the core of the main subcluster of Abell 2028 taken from a 0.5′ aperture (corresponding to region 1 of Fig. 4). Data from MOS1, MOS2, and pn are plotted in black, red, and green, respectively. The best-fit model obtained from a 1T fit in the broad band 0.5 − 10 keV and residuals are also shown. Central panel: MOS 1 spectrum from the inner core corresponding to region 1. Three different spectral models are overplotted: the 1T model (green line) fitted in the broad 0.5 − 10 keV band; the 1T model fitted in the 0.5 − 3 keV band (red line) and the 1T model with the parameters obtained by the 0.5 − 10 keV fit, but with the abundance value kept fixed at the lower value obtained in the 0.5 − 3 keV band (blue line). Right panel: same as in the left panel with the best-fit 2T model (with the higher temperature fixed at 5 keV) in the 0.5 − 10 keV band.