WASHINGTON:NASA’s Chandra X-ray Observatory has found evidence of powerful blasts of gases produced by a super massive black hole about 26 million light years from Earth, an event that may trigger the formation of new stars.
This is one of the nearest super massive black holes to Earth that is currently undergoing such violent outbursts, researchers said.
Astronomers found this outburst in the super massive black hole centred in the small galaxy NGC 5195. This companion galaxy is merging with a large spiral galaxy NGC 5194, also known as “The Whirlpool.” Both of these galaxies are in the Messier 51 galaxy system, located about 26 million light years from Earth. “For an analogy, astronomers often refer to black holes as ‘eating’ stars and gas. Apparently, black holes can also burp after their meal,” said Eric Schlegel of The University of Texas, who led the study. “Our observation is important because this behaviour would likely happen very often in the early universe, altering the evolution of galaxies,” he said. “It is common for big black holes to expel gas outward, but rare to have such a close, resolved view of these events,” he said. In the Chandra data, the researchers detect two arcs of X-ray emission close to the centre of NGC 5195. “We think these arcs represent fossils from two enormous blasts when the black hole expelled material outward into the galaxy,” said Christine Jones of the Harvard-Smithsonian Centre for Astrophysics (CfA) in US. Just outside the outer X-ray arc, the scientists detected a slender region of emission of relatively cool hydrogen gas. This suggests that the hotter, X-ray emitting gas has “snow-plowed,” or swept up, the hydrogen gas from the centre of the galaxy. This is a clear case where a super massive black hole is affecting its host galaxy in a phenomenon that astronomers call “feedback.” In NGC 5195, the properties of the gas around the X-ray-glowing arcs suggest that the outer arc has plowed up enough material to trigger the formation of new stars. “We think that feedback keeps galaxies from becoming too large. But at the same time, it can be responsible for how some stars form. This shows that black holes can create, not just destroy,” said co-author Marie Machacek of CfA. The outbursts of the super massive black hole in NGC 5195 may have been triggered by the interaction of this smaller galaxy with its large spiral companion, causing gas to be funnelled in towards the black hole, researchers said. The energy generated by this infalling matter would produce the outbursts. The team said that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc. They may represent a rare view an intermediate stage in the feedback process operating between the interstellar gas and the black hole, researchers said.–PTI
