Deep near-infrared imaging of the HE0450-2958 system

The quasar HE0450-2958 has until now been a puzzle, since nobody had detected its host galaxy. It is interacting with a companion galaxy that is ultra luminous in the infrared. Many hypotheses have been invoked, such as the ejection of the black hole by the galaxy through relativistic recoil or jet induced star formation. Deep observations in the near-IR with the ESO VLT and HAWK-I have led to the discovery of stellar emission around the quasar, reported in this work for the first time. The emission can be interpreted as an off-center, bright and very compact host galaxy that is involved in a violent collision with its companion.