Astronomy picture of the day 28-09-2014 - Two Black Holes Dancing in 3C 75

Two Black Holes Dancing in 3C 75
Image Credit: X-Ray:NASA/CXC/D. Hudson, T.Reiprich et al.(AIfA); Radio: NRAO/VLA/NRL

Explanation: What's happening at the center of active galaxy 3C 75? The two bright sources at the center ofthis composite x-ray (blue)/radio(pink) image are co-orbiting supermassive black holes powering the giant radio source3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles thesupermassive black holesare separated by 25,000 light-years. At the cores oftwo merging galaxies in theAbell 400 galaxy cluster they are some 300 million light-years away.Astronomers conclude that these two supermassiveblack holes are bound together by gravity in a binary systemin part becausethe jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowdedgalaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources ofgravitational waves.