Left: optical image of the Carina nebula complex (from: www.eso.org/public/images/eso0905b/; image credit: ESO/Digitized Sky Survey 2, Davide De Martin). The region observed in the context of the Chandra Carina Complex Project (CCCP) and the Chandra pointing of the Gum 31 region are marked by the cyan outlines. Right: optical image of the Gum 31 region obtained with the Wide Field Imager on the MPG/ESO 2.2 m telescope at La Silla Observatory (from: www.eso.org/public/images/eso1207a/; image credit: ESO) with outline of the Chandra pointing in cyan. The individual X-ray point sources are marked by green crosses. The yellow boxes mark the two regions shown in Fig. 5 (box A corresponds to the region of the cluster NGC 3324, while box B corresponds to the region of the cluster G286.38−0.26).