Spectral energy distribution of GX 13+1 in EF_E representation as observed by IXPE in bin 1. The left, middle, and right panels show the Stokes parameters I, Q, and U, respectively. The fit is performed in the 2–8 keV energy band using the three IXPE detectors and applying the model tbabs*pollin*(diskbb+bbodyrad). The total model is shown with the solid black line, and diskbb and bbodyrad are shown with the dashed and dotted lines, respectively. The lower subpanels show the residuals between the data and the best fit. The data are rebinned only for plotting purposes.