MS 0735.6+7421 is a galaxy cluster.
The most powerful explosion since the big bang occurred there. Using data from the Chandra Space Telescope, scientists have deduced that an explosion several hundred million times as powerful as a gamma ray burst took 100 million years to occur at the heart of the galaxy cluster. The remnants of the explosion are seen as two cavities on either side of a large central galaxy. It is estimated that over 300 million solar masses of material infell to the supermassive black hole, resulting in the explosion. The projected mass consumed is larger than many super-massive black holes in and of itself.