Polarization degree as a function of energy derived from bldisk using the same parameter combination as that reported in Fig. 4. For axisymmetric geometries PD =|Q|, so angle rotation with PA switching from orthogonal (Q > 0) to parallel (Q < 0) direction to the symmetry axis occurs at the energy where PD =0. The vertical lines represent the IXPE energy bands 2–4 keV and 4–8 keV, respectively.