This composite X-ray (blue)/radio (pink) image of the galaxy cluster Abell 400 shows radio jets immersed in a vast cloud of multimillion degree X-ray emitting gas that pervades the cluster. The jets emanate from the vicinity of two supermassive black holes (bright spots in the image). Credit: X-ray: NASA/CXC/AIfA/D.Hudson & T.Reiprich et al.; Radio: NRAO/VLA/NRL
