Widespread galactic cannibalism in Stephan’s Quintet revealed by CFHT

An extremely deep multi-band optical image from the Canada-France-Hawaii Telescope (CFHT, Hawaii. USA) casts a new light on the formation process of the famous group of 5 colliding galaxies. The image reveals structures undetected thus far, in particular a very extended red halo composed of old stars, and centered on an elliptical galaxy, NGC 7317, which had been ignored in previous studies on the dynamics of the global collision. These results are published in the Monthly notices of the Royal Astronomical Society by a team from the Observatoire Astronomique de Strasbourg (France), CEA Saclay (France) and the Lund Observatory (Sweden).