Left column: distribution of the temperature of the diffuse dust with galactocentric distance. Each point represents a dust cell in our simulations. They are colour-coded according to f_young. The level of transparency indicates the point density. The bulge radius is indicated with a vertical red line while the vertical blue line denotes the outer truncation radius of the Ferrers-bar. The dashed black line is the running median through the data points. Right column: face-on view of the dust temperatures as obtained from the 3D dust cell distribution, for each galaxy. The bulge region is indicated with a solid red circle and the bar region with a dashed blue ellipse.