Black hole jet seen flaring wildly

Posted by Kate Taylor

NASA's busy Wide-field Infrared Survey Explorer (WISE) has captured rare data of a flaring black hole releasing a blazing jet.

The black hole, called GX 339-4, lies more than 20,000 light-years away, near the center of our galaxy, and has a mass at least six times that of the sun.

It's orbited by a companion star that feeds it - and, while most of the material from the companion star is pulled into the black hole, some is blasted out as a jet at nearly the speed of light.

"Imagine what it would be like if our sun were to undergo sudden, random bursts, becoming three times brighter in a matter of hours, and then fading back again. That's the kind of fury we observed in this jet," says Poshak Gandhi, a scientist with the Japan Aerospace Exploration Agency (JAXA).

"With WISE's infrared vision, we were able to zoom in on the inner regions near the base of the stellar-mass black hole's jet for the first time and the physics of jets in action."

NEOWISE, the asteroid-hunting portion of the WISE mission, captured images of the same patch of sky over time, allowing the team to zoom in on the very compact region around the base of the jet streaming from the black hole.

This, they say, is equivalent to observing something the width of a dime, as far away as the sun.

The results surprised the team, showing huge and erratic fluctuations in the jet activity on timescales ranging from 11 seconds to a few hours. In addition, the size of the jet's base varies by afactor of 10 or more.

"If you think of the black hole's jet as a firehose, then it's as if we've discovered the flow is intermittent and the hose itself is varying wildly in size," Poshak said.

The new data also allowed astronomers to make the best measurements yet of the black hole's magnetic field, which is 30,000 times more powerful than the one generated by Earth at its surface.