Weird Black Hole shoots squeaks because he's dragging space-time

Some 7,800 light-years away from the constellation Cygnus is a very special black hole. It's called V404 Cygni, and in 2015, telescopes from around the world marveled as they emerged from dormancy to devour the contents of a star over the course of a week.

This event provided such a wealth of information that astronomers are currently analyzing it. And they have just discovered an amazing event: relativistic jets flickering so quickly that their change of direction can be seen in just a few minutes.

And, in doing so, they inflate plasma clouds at high speed.

"It's one of the most extraordinary black hole systems I've ever encountered," said astrophysicist James Miller-Jones of the International Center for Research in Radioastronomy (ICRAR) from Curtin University in Australia.

The V404 Cygni is a binary microquasar system consisting of a black hole representing approximately nine times the mass of the Sun and a companion star, an early red giant slightly smaller than the Sun.

The black hole slowly devours the red giant; the material that siphons from the star rotates around the black hole in the form of an accretion disk, much like water surrounding a drain. The regions closest to the disc are incredibly dense, warm and extremely radiant; and, as the black hole feeds, it throws powerful jets of plasma, presumably from its poles.

Scientists do not know the precise mechanism behind the production of jets. They think that the materials of the inner edge of the accretion disk are routed along the magnetic field lines of the black hole, which act as a synchrotron to accelerate the particles before launching them at huge speeds.

But the unstable jets of the V404 Cygni, flying in different directions at different times, on such rapidly changing time scales and at speeds up to 60% of the speed of light, are a class apart.

"We think the disc of material and the black hole are misaligned," Miller-Jones said. "It seems to swing the inner part of the disc like a spinning top and trigger jets in different directions as the orientation changes."

It's a bit like a spinning top that starts to wobble as it slows down, the researchers said. This change of axis of rotation of a rotating body is called precession. In this particular case, we have a practical explanation provided by Albert Einstein.

In his theory of general relativity, Einstein predicted an effect called dragging images. When it rotates, the gravitational field of a rotating black hole is so intense that it essentially causes space-time with it. (This is one of the effects that scientists hoped to observe when taking a photo of Pōwehi.)

In the case of V404 Cygni, the accretion disk is about 10 million kilometers (6.2 million miles). The misalignment of the axis of rotation of the black hole with the accretion disk has distorted the few thousand inner kilometers of this disk.

The drag effect then drives the deformed part of the disc with the rotation of the black hole, which sends the jet in all directions. In addition, this inner section of the accretion disk is inflated as a solid donut that also precedes.

"This is the only mechanism we can think of that can explain the rapid precession seen in the Cygni V404," Miller-Jones said.

It's so fast that the usual method of radio telescopes for the imaging space was virtually useless. Usually, these devices are based on long exposures, observing a region for several hours at a time, moving in the sky to follow their target. But in this case, the method produced images too fuzzy to be useful.

So the team had to use a different method, taking 103 separate images with exposure times of just 70 seconds and assembling them together to create a movie – and of course, there were jets of Space-time vacillating and trembling.

"We were amazed by what we saw in this system – it was completely unexpected," said physicist Greg Sivakoff of the University of Alberta.

"The discovery of this astronomical first has deepened our understanding of how black holes and galaxy formation can work, and it tells us a bit more about this big question:" How did we get here? "

The search was published in Nature.