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Black hole creating cosmic hurricane

blackholewinds 220212

The stellar mass black hole sucks matter from a companion star and blows most of it back into space at incredible speed (Source: NASA/CXC/M.Weiss)

Record winds Astronomers discover some of the fastest winds ever detected coming from a black hole near the centre of our galaxy.

The record-breaking winds were clocked at more than 32 million kilometres per hour, or three per cent of the speed of light.

The findings help scientists better understand these giant gravity wells, where light cannot escape and the laws of physics breakdown.

Stellar-mass black holes are created by the supernova death of a star five to ten times the mass of the Sun.

Astronomers from the University of Michigan were studying a stellar mass black hole called IGR J17091-3624 when they made the stellar wind discovery.

The black hole is in a binary system with a Sun-like star in the middle of the Milky Way, 28,000 light-years from Earth.

Using NASA's Earth orbiting Chandra x-ray Observatory, the researchers detected gas being blown off the black hole's accretion disk.

The disk is a superheated soup of debris and plasma where stars, planets and other matter is crushed, stretched and torn apart before falling beyond the black holes event horizon and disappearing forever into the singularity.

Using spectroscopic readings of iron atoms emanating from the disk, King and colleagues clocked wind speeds matching some of the fastest winds generated by supermassive black holes, which can be billions of times larger.

"This is like the cosmic equivalent of winds from a category five hurricane," says study lead author Ashley King.


Winds linked to jets

Writing in the Astrophysical Journal Letters, King and colleagues report seeing winds blowing at times when highly focused jets of material normally produced by a black hole feeding have died down.

These jets shoot out perpendicular to the disk at near light speed.

The findings were confirmed by simultaneous observations made with the Expanded Very Large Array in New Mexico.

A Chandra spectrum of iron ions made two months earlier showed no evidence of the high-speed wind, indicating they turn on and off over time.

King and colleagues also found the wind may be carrying away more material than the black hole is capturing.


Ten times faster

Dr Sean Farrell from the University of Sydney says, "This is an extremely active black hole in our own galaxy".

"It's pushing winds nearly ten times faster than any previous winds detected coming from stellar-mass black holes," says Farrell.

"That puts it right up there with the behaviour we normally see in supermassive black holes."

As to what's generating the winds, Farrell says, "This remains an active field of research".

"We think the jets may be caused by magnetic fields twisted up in the disk," says Farrell.

"But, the authors think the winds are being launched from the outer edges of the accretion disk, created by a thermal mechanism generated by the disk's hotter inner edges."

"However, If they were produced closer in, they would also be magnetic in origin," says Farrell.

Tags: blackholes, physics, stars, galaxies