Results of the phase-resolved spectro-polarimetric analysis of Vela X-1 based on the IXPE data at low energies (LE; 2−3 keV; left) and high energies (HE; 5−8 keV; right). Top panels: Pulse profiles (in counts) corresponding to the low- and high-energy ranges. Middle and bottom panels: Pulse-phase dependence of the PD and PA, respectively. The NuSTAR pulse profile in the 15−45 keV energy band is displayed in the PD panels (light blue). The orange curve in the PA panel shows the best-fit RVM to the data in the high-energy range.