Top left panel: difference between the sharpness angles of the Maxwellian synchrotron function and the re-fitting models, θ_maxw−θ_model, as a function of x_left. Top right panel: same for θ_maxw−θ_BAND. Bottom left panel: same for θ_left,maxw−θ_left,model. Bottom right panel: same for θ_left,maxw−θ_left,BAND. The red vertical lines show the NaI detector limit of 8 keV ~ 0.03E_p for E_p ~ 250 keV. The shaded regions show the 1σ regions. See main text for details about the plots.