Left panel: PACS 160 μm radial surface brightness profile of NGC 1140; open (blue) circles give the profile obtained from azimuthally averaging the image, and filled (red) squares the analogous profile obtained from the first derivative of the photometric growth curve. The lower dashed curve show an exponential distribution of scale length 6.̋4 convolved with the PACS 160 μm beam (assuming it is Gaussian), and the upper one the same exponential but without convolution. Right panel: PACS 160 μm growth curve centered on the brightness peak. The left-most dotted vertical line gives the PACS beam radius (~5.̋5) and the right-most one the optical radius of NGC 1140 taken from NED (51′′). The solid grey curve corresponds to the best-fit exponential integral as described in the text.