Sagittarius A
The European Space Agency's gamma-ray observatory INTEGRAL has observed gamma rays interacting with Sgr B2, causing X-ray emission from the molecular cloud. This energy was emitted about 350 years ago by the supermassive black hole (SMBH) at the galaxy's core, Sagittarius A*. The total luminosity from this outburst is an estimated million times stronger than the current output from Sagittarius A*. This conclusion has been supported in 2011 by Japanese astronomers who observed the galactic center with the Suzaku satellite.