The upper panels show the best-fit temperatures (asterisks) and the 1σ uncertainties (boxes) in the hard band obtained with the XMM-Newton instruments pn (left panel), MOS1 (middle panel) and MOS2 (right panel). The lower panels show the relative temperature difference, f_T = ΔT /  ⟨ T ⟩  (diamonds), and its 1σ uncertainty for MOS1-pn (left panel), MOS2-pn (middle panel) and MOS2-MOS1 (right panel). The dotted and dashed lines show the weighted mean of f_T  ±  the error of the mean.