Stokes parameters and PA profiles for our analytical OS model (blue curve), the exact result of ARCMANCER with AGM model (dashed black curve), and the S+D model from Viironen & Poutanen (2004; green curve). The panels, from top to bottom, show the flux normalized to the maximum, the normalized Stokes parameters F_Q and F_U, the PA, and the difference in PA (χ_AGM − χ_OS in red and χ_AGM − χ_S + D in orange), respectively. The blue and black curves almost completely overlap. The parameters used to calculate the profiles are the same as in Fig. 5, except for a spherical star we use the mass and radius of the corresponding non-rotating NS of the same baryonic mass: M₀ = 1.394 M_⊙ and R₀ = 11.43 km (see Sect. 2.1).