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FEBRUARY 22 2012 01:25h

Black hole offering up cosmic surprise


CAMBRIDGE, Mass., Feb. 21 (UPI) -- U.S. astronomers say they used an X-ray observatory to clock the fastest particle wind yet discovered blowing off a disk around a stellar-mass black hole.

Researchers at the Chandra X-Ray Observatory Center at Harvard University say the observations have important implications for understanding how this type of black hole behaves.

The record-breaking wind is moving about 20 million mph, or about 3 percent of the speed of light, nearly 10 times faster than had ever been seen from a stellar-mass black hole, the Chandra center reported Tuesday.

"This is like the cosmic equivalent of winds from a Category 5 hurricane," study lead author Ashley King from the University of Michigan said. "We weren't expecting to see such powerful winds from a black hole like this."

Particle winds of this speed are usually seen only around truly massive black holes, the researchers said.

The stellar-mass black hole powering this super wind is known as IGR J17091.

"It's a surprise this small black hole is able to muster the wind speeds we typically only see in the giant black holes," co-author Jon M. Miller, also from the University of Michigan, said. "In other words, this black hole is performing well above its weight class."

The wind, from a disk of gas surrounding the black hole, may be carrying away more material than the black hole is capturing, King said.

"Contrary to the popular perception of black holes pulling in all of the material that gets close, we estimate up to 95 percent of the matter in the disk around IGR J17091 is expelled by the wind," King said.