Scatter plot of and fitted dust temperature for the modified black-body fit. Two alternative estimates of A_V are shown (see text), plus an average value. The horizontal grey lines show and the 15% uncertainty in the A_V normalisation (Sect. 2.1). All points have similar relative uncertainty; the bars for the lowest U_min are shown. The uncertainties are systematic, so they affect each point in the same way; errors on the two axes are strongly anti-correlated. The U_min colour scheme is the same as Fig. 2; the filled symbols correspond to the SEDs shown in Fig. 1.