Astronomers find black hole outburst
13 April 2011
'Eye of Sauron' outburst aids astronomers' understanding of black hole growth
Professor Carole Mundell from the Astrophysics Research Institute (ARI), alongside colleagues in USA, Italy, Germany and Greece, have used NASA's Chandra X-ray satellite to show that the supermassive black hole lurking at the centre of the spiral galaxy, NGC4151 (dubbed The 'Eye of Sauron' by astronomers due to its resemblance to the character in 'The Lord of the Rings' movies) powered an outburst of high energy X-rays as recently as 25,000 years ago.
Powered by the release of gravitational potential energy as material from the host galaxy is accreted by the central supermassive black hole, active galaxies are thought to form a vital part in the life cycle of every large galaxy through cosmic epoch, but the detailed physics and consequences of this cosmic black-hole feeding and indigestion remain debated.
NGC 4151 is located about 43 million light years away from the Earth and is one of the nearest galaxies which contains an actively growing black hole. Due to this proximity, it offers one of the best chances of studying the interaction between an active supermassive black hole and the surrounding gas of its host galaxy.
The relatively short amount of time since the last episode of high activity by the black hole inferred by the team, who combined datasets taken at X-ray, optical and radio wavelengths to form a comprehensive view of the physics of this active galaxy, has important implications for astronomers' understanding of black-hole growth and the impact of their activity on their surrounding galaxy through cosmic epoch. This may also imply such outbursts occupy at least 1% of a supermassive black hole's lifetime.
More details can be found at: http://www.nasa.gov/mission_pages/chandra/multimedia/11-029.html
Pictured: An Active Black Hole in The 'Eye of Sauron'