Chandra catches 'piranha' black holes

These galaxy clusters show that younger, more distant galaxy clusters contained far more active galactic nuclei (AGN) than older, nearby ones. It was found that the clusters at 58 percent of the Universe’s current age contained about 20 times more AGN than those at 82 percent of Universe's age. The galaxies in the earlier Universe contained much more gas that allowed for more star formation and black hole growth. In the Chandra X-ray images, red, green, and blue represent low, medium, and high-energy X-rays. Credit: NASA/CXC/OSU/P. Martini et al.