'Extraordinary' Black Hole Shoots Out 'Swinging' Jets of Plasma at High Speed in Never-before-seen Phenomenon

Black hole, V404 Cygni
Artist's impression of V404 Cygni seen close up. The binary star system consists of a normal star in orbit with a black hole. Material from the star falls toward the black hole and spirals inwards in an accretion disk, with powerful jets being launched from the inner regions close to the black hole. ICRAR

An international team of astronomers has observed a never-before-seen phenomenon taking place at an "extraordinary" black hole, according to a study published in the journal Nature.

With the help of observatories around the world, the team witnessed rapidly swinging jets of plasma—a gas which has been heated until the electrons become detached from their parent atom or molecule—shooting out of the black hole in different directions at close to the speed of light.

"This is one of the most extraordinary black hole systems I've ever come across," James Miller-Jones, an author of the study from the International Centre for Radio Astronomy Research, said in a statement.

The black hole—which has a mass about nine times that of our sun—is located in a double-star system known as V404 Cygni, roughly 7,800 light years from Earth. Essentially, the black hole is in a 6.5-day orbit with a normal star about 70 percent the mass of the sun.

"The two are separated by about 20 million kilometers [12 million miles]; close enough that the gravity of the black hole is able to pull the outer layers off the star, with the gas then swirling in towards the black hole in a thin disk-like structure known as an accretion disk," Miller-Jones told Newsweek.

"In June of 2015, the system underwent a very bright outburst in which the black hole started feeding extremely rapidly. Astronomers across the globe trained their telescopes on it, providing intensive observational coverage of a black hole feeding close to its maximum possible rate," he said.

Using the Very Long Baseline Array—an intercontinental system of 10 radio telescopes operated from a center in Socorro, New Mexico—the team observed the jets at a high resolution, equivalent to seeing a quarter in New York from the distance of Los Angeles.

"What our results showed to be unusual was that the jets in this system appeared to move away from the black hole in different directions at different times, with the direction changing on timescales of hours, or even minutes," Miller-Jones said. "While jets are usually seen moving away in opposite directions from a feeding black hole, it is rare to see the jet direction changing over time, particularly on such short timescales."

In the study, the researchers propose a possible explanation for this unusual phenomenon: The intense radiation from the rapidly feeding black hole caused the inner few thousand miles of the accretion disk to puff-up into a doughnut-shaped structure.

"Because the axis about which the black hole was spinning was not the same as the axis of the binary orbit, the puffed up disk was forced to wobble about the black hole spin axis like a spinning top that is slowing down," Miller-Jones said.

"This shows us that the dynamics of the inflowing gas—how the gas is moving as it falls in towards the black hole—can affect the behavior of the jets," he said.

According to the team, this could have implications for our understanding of other similar extreme events in the universe.

"We think the same physics should hold in other black holes and could be seen any time a spinning black hole is feeding rapidly from a gas reservoir that is not aligned with the black hole's rotation axis," Miller-Jones said. "This could apply to other stellar-mass black holes, or even to the supermassive black holes in the centres of galaxies that rip apart an unlucky star that wanders too close, and feed on the resulting debris."