Evidence of jet in Milky Way`s supermassive black hole found

Washington: Astronomers, who have long sought strong evidence that Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is producing a jet of high-energy particles, have finally found it.

The astronomers used NASA`s Chandra X-ray Observatory and the National Science Foundation`s Very Large Array (VLA) radio telescope to make the finding. Previous studies, using a variety of telescopes, suggested there was a jet, but these reports-including the orientation of the suspected jets-often contradicted each other and were not considered definitive. "For decades astronomers have looked for a jet associated with the Milky Way`s black hole. Our new observations make the strongest case yet for such a jet," lead author Zhiyuan Li of Nanjing University in China, said. Jets of high-energy particles are found throughout the universe, on large and small scales. They are produced by young stars and by black holes a thousand times larger than the Milky Way`s black hole. They play important roles in transporting energy away from the central object and, on a galactic scale, in regulating the rate of formation of new stars. The jet appears to be running into gas near Sgr A*, producing X-rays detected by Chandra and radio emission observed by the VLA. The two key pieces of evidence for the jet are a straight line of X-ray emitting gas that points toward Sgr A* and a shock front-similar to a sonic boom-seen in radio data, where the jet appears to be striking the gas. Additionally, the energy signature, or spectrum, in X-rays of Sgr A* resembles that of jets coming from supermassive black holes in other galaxies. The findings are published online in The Astrophysical Journal.