XMM-Newton digs into the secrets of fossil galaxy clusters

XMM-Newton observations of the fossil galaxy cluster RX J1416.5+2315, show a cloud of hot gas emitting X-rays (in blue). The cloud, reaching temperatures of about 50 million degrees, extend over 3.5 million light years and surround a giant elliptical galaxy believed to have grown to its present size by cannibalising its neighbours. Credits: Khosroshahi, Maughan, Ponman, Jones, ESA, ING