Phase-folded light curves of the normalisations of the thermal components and of their ratio. Left: variation over phase of the normalisation (norm1) of the soft thermal component (kT =0.67 keV). Middle: same as the left panel but for the hard thermal component (norm2; kT =2.97 keV) Right: variation over phase of the normalisation ratio (norm1/norm2) and its weighted linear fit shown with the solid red line.