Tuesday , November 19 2019
Home / unitedkingdom / Black hole misaligned at just 8,000 light-years from Earth is behaving strangely | Science and technology news

Black hole misaligned at just 8,000 light-years from Earth is behaving strangely | Science and technology news



Scientists have discovered a "misaligned" black hole just 8,000 light years from Earth – and it's behaving in a way never seen before.

Researchers at the International Center for Radio Astronomy Research (ICRAR) have published their findings on the black hole V404 Cygni in the journal Nature.

They have never seen a black hole behaving so strangely before – with its spitting radio jets spinning with high-velocity plasma clouds that are coming out of it in different directions.

Artist impression of V404 Cygni seen close up. The binary stellar system consists of a normal star in orbit with a black hole. The material of the star falls into the black hole and spirals in on an accretion disk, with powerful jets being launched from the inner regions near the black hole. Credit: ICRAR
Image:
The impression of a V404 Cygni artist seen close up. Image: ICRAR

Lead author of the study, Associate Professor James Miller-Jones, said: "This is one of the most extraordinary black hole systems I have ever seen.

"Like many black holes, he is feeding on a nearby star, pulling the gas away from the star and forming a disk of material that circles the black hole and spirals toward it under gravity.

"What's different about the Cygni V404 is that we think the material disk and the black hole are misaligned."

This misalignment means that the inner part of the black hole disc is swinging like a top, causing the jets to be fired in different directions as it changes orientation.

The black hole in Cygni V404 was discovered in 1989 after a huge explosion of jets and radiation.

According to associate professor Miller-Jones, another very bright explosion in 2015, lasting two weeks, led telescopes around the world to tune in and study what was happening.

"They all jumped in the blast with any telescopes they could launch, so we have this incredible observational coverage," he said.

When the ICRAR team studied the black hole, they realized that the jets were behaving in ways never seen before.

Usually jets shoot directly from the black-hole poles, but these jets were seen firing in different directions at different times-and they were changing direction quickly every two hours.



First image released by the collaboration of scientists after a two-year project gathering data



The first image of a black hole

Associate Professor Miller-Jones said that this change was because of the accretion disk, the disk of matter around the edge of the black hole that was falling on it.

"The inner part of the accretion disk was precessor and effectively pulled the jets with it," said associate professor Miller-Jones.

"You can think of it as the spinning of a spinning top while it slows down – only in this case, the oscillation is caused by Einstein's theory of general relativity."

The artist's impression of space-time twisted around the rotating black hole. The black hole is so dense that it creates a rupture in the fabric of space time, seen here as the well infinitely deep in the center. As the black hole rotates, it drags space-time with it, giving rise to the twisting of the space-time grid shown here. This leads to the precession of the swollen internal accretion disc. Credit: ICRAR
Image:
The impression of a space-time artist twisted around the rotating black hole. Image: ICRAR

Study co-author Alex Tetarenko said that the speed with which the jets were changing direction meant that scientists had to use a very different approach to most radio observations.

"Typically, radio telescopes produce a single image from several hours of observation," she said.

"But these jets were changing so fast that in a four-hour image we just saw a blur.

"It was like trying to take a picture of a waterfall with a shutter speed of one second."

Instead, the researchers produced 103 individual images, each about 70 seconds long, and put them together in one film.

"It was just by doing this that we could see these changes in a very short period of time," said Tetarenko.

Another coauthor, Dr. Gemma Anderson, said, "Whenever you have a misalignment between the turning of a black hole and the material falling in, you would expect to see this when a black hole begins to feed very quickly.

"This may include a lot of other explosive events in the Universe, such as supermassive black holes that feed very quickly or events of tidal rupture, when a black hole rips a star."


Source link