Four Stokes V/I_c profiles with the largest amplitude belonging to BP (b), and their corresponding Stokes I/I_c profiles. The various Stokes I (V) profiles are shifted by +0.20 (+0.05) along the y-axis or ordinate. The wavelength axis is centered at the Si I line at rest. The red line shows the best fit obtained from the SIR inversion. The dotted vertical lines show the positions at rest of Si I and of the blue (He I b) and red (He I r) components of He I. The dashed vertical line indicates Si I λ₀ − 0.35 Å, which corresponds to the image shown in the lower right corner of Fig. 1.