HXD spectra of A2163 in the 10–60 keV band for the central region a) and the northeast region b). In each panel, observed HXD data denoted as “Data”, the NXB model, the CXB model, and the background-subtracted data, “Data – (NXB+CXB)”, are shown using black crosses, red crosses, green crosses, and black circles, respectively. The point-source contribution estimated from the XMM-Newton observations of the same field is shown using blue crosses.