Blazar 3C 279 gamma-ray flare. Gamma-ray image of a galaxy 3C 279 (centre) during a flare occurring between June 11th and June 17th 2015. The plane of the Milky Way appears as a curve (lower frame). The Vela pulsar, usually the brightest gamma-ray object in the sky, appears lower right and is outshone by the increased energy output of 3C 279. A blazar is a galaxy whose high-energy activity is powered by a central supermassive black hole. As matter falls toward the black hole, some particles race away at nearly the speed of light along a pair of jets pointed in opposite directions. A blazar can be detected when one of these particle jets happens to be directed towards Earth. Image created from data from the Large Area Telescope (LAT) on NASA's Fermi satellite.