Top panel: Model photon spectra for O-mode (dashed lines) and X-mode (solid lines) modes from RICS (pink), splitting (purple), and pair synchrotron (green) radiation from a pair cascade from electrons on a closed magnetic field loop with ﹩{r}_{{\rm{\max }}}=6﹩ neutron star radii, surface magnetic field strength B = 32 B_cr, viewing angle, θ_v = 30°, scattering photons from the whole neutron star surface with temperature 5 × 10⁶ K. Light lines are unattenuated spectra, and dark lines are attenuated (observed) spectra. The normalization is arbitrary. The solid black/red lines are the soft, hard, and total model fits of IXPE/NuSTAR data. The IXPE model has been multiplied by a factor of 1.4 to correct for the calibration uncertainty with NuSTAR. Bottom panel: polarization degree of the total attenuated spectrum.