Data of Mrk 1044, SDSS J080101.41+184840.7, and IRAS 04416+1215. Plots, from top to bottom: total flux, Stokes parameters U and Q, flux of U and Q, and the polarization angle. We mark in red the windows in which we calculated polarization. For continuum polarization, we considered two surrounding Hα from its blue and red side, each window has a width of ≈100 Å, and they are at a distance of at least 300 Å from the center of Hα. For the polarization of the line, we considered the red window mark on the line. Each central window has width of ≈50 Å. The vertical blue dotted line marks the central wavelength for Hα. The data were rebinned with a 2 Å binning.