WISE colour–colour diagram showing the CHILLING galaxies in dependency of their detectability category of RC emission, while showing in the background the locations of interesting classes of objects (Wright et al. 2010). Dwarf galaxies with diffuse RC emission are shown in green, those with compact RC emission are shown in blue, and non-detections or weak detections are shown in orange. The WISE W1, W2 and W3 bands are 3.4 μm, 4.6 μm and 12 μm, respectively.