Chandra X-ray & DSS Optical Images of SDSS J1254
These images show the effects of two galaxies caught in the act of merging. A Chandra X-ray Observatory image shows a pair of quasars located about 4.6 billion light years away, but separated on the sky by only about 70 thousand light years. These bright sources, collectively called SDSS J1254+0846, are powered by material falling onto supermassive black holes. An optical image from the Baade-Magellan telescope in Chile shows tidal tails - gravitational-stripped streamers of stars and gas -- fanning out from the two colliding galaxies.
(Credit: X-ray (NASA/CXC/SAO/P. Green et al.), Optical (Carnegie Obs./Magellan/W.Baade Telescope/J.S.Mulchaey et al.))