Residuals of the N2 flux-resolved spectra (FPMA in gray; FPMB in varying colors). The dashed orange lines mark the CRSF positions, using the values listed in Table B.1. Renormalizing the spectral model to the source flux without changing spectral parameters results in the χ² residuals (a) and ratio (b). Refitting the parameters of the four flux-resolved spectra simultaneously leads to the best fit (c). (d): Contribution of the “10 keV feature”, showing the resulting ratio after removing the component from the best-fit.