Top: from left to right, L183 original image in galactic coordinates from the HCS survey (IRAC 1, 3.6 μm), point sources and background-subtracted image showing the 3.6 μm coreshine intensity (with a Gaussian smoothing), and coreshine ratio (4.5/3.6) image. The white line shows the position of the cut presented below, the white cross indicates the zero-position reference. Bottom left: the profile through the cut for the source data (black) and through the cleaned and smoothed image (red); the 3.6 μm coreshine zone is highlighted by the red shading. The intensities are given in MJy sr^-1. The cut has been chosen to fit both a region with strong coreshine intensity (~50 kJy sr^-1 here) and to show the internal depression, which traces self-absorption, ~2.5 arcmin from the zero reference, marked by the red arrow on the profile. Bottom right: the coreshine ratio histogram. The blue line displays the FWHM of the histogram.