The overlooked dwarf and its apparent companion

Colour image of the two galaxies NGC 5011B (top) and NGC 5011C (bottom blue galaxy). NGC 5011C is a dwarf galaxy located in the Centaurus A group, while its companion on the sky is in fact an S0 galaxy, located 12 times further away and belonging to the Centaurus cluster of galaxies. The composite image is based on data obtained with the EFOSC2 instrument on the ESO 3.6-metre telescope at the La Silla Observatory in three different wavebands (B, V, and R). The total integration time is 3 minutes. The field of view is about 5 x 4.5 arcmin. North is up, East to the left.