Illustration of the warm background subtraction detection processing on a Galactic patch of 10° × 10° centered on ( − 40°, 0°). The upper left map is the original 545   GHz map, from 0 to 500 MJy/sr. In the right upper panel is the cold residual at 545   GHz after subtraction of the warm component extrapolated from the 2997   GHz. From the cold residual map are then computed the background and 1-σ maps, respectively left and right middle panels, plotted from  − 5 MJy/sr to 5 MJy/sr. The signal-to-noise map S/N is given in the lower left panel, plotted in the range 4 to 10. The simulated cold cores only map is shown at 545   GHz in the lower right panel, with a colour scale ranging from 0 to 5 MJy/sr. We observe a good agreement between detections and real positions of cold cores.