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Friday, 26 May, 2000, 09:19 GMT 10:19 UK
Chandra homes in on a black hole
Nasa
X-rays from the black hole are spread into its component parts by Chandra
By BBC News Online science editor Dr David Whitehouse

The Chandra X-ray Observatory has looked at the violent region around a giant black hole in a distant galaxy.


Nasa
Artist's impression of the Chandra observatory
Chandra has observed the dramatic effects of intense radiation produced by matter before it plunges into the black hole. This radiation heats surrounding gas and drives a high speed wind away from the grip of the black hole's gravity.

"X-ray observations allow astronomers to probe these extremely powerful gas flows that have been suspected to exist, but have been impossible to study precisely before," said Professor Niel Brandt of Pennsylvania State University.

Commenting on the Chandra data Dr. Shai Kaspi, also of Penn State said, "This is the most detailed X-ray spectrum ever taken of a galaxy with an active black hole."

"It reveals that the wind contains oxygen, neon, magnesium, silicon, sulphur, argon, and iron."

Billion suns

An analysis of the wind by Professor Hagai Netzer of Tel-Aviv University in Israel, showed that the wind almost completely surrounds the black hole.

The so-called event horizon of the central black hole in the galaxy, designated NGC 3783, has a diameter about a hundred times that of our Sun.

The black hole produces more radiation than a billion suns as gas is sucked into it at nearly the speed of light. A portion of this powerful radiation is absorbed by the gas that surrounds the black hole. The gas is heated to a hundred thousand degrees or more and driven away from the black hole.

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30 Nov 99 | Sci/Tech
X-raying the violent Universe
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