Astronomers have detected plasma jets spraying from a rapidly spinning black hole, about 8000 light-years away. It is warping spacetime around it.
We are talking about V404 Cygni’s black hole which lies within our galaxy. It is behaving in a way never seen before in such a short time.
“This is one of the most extraordinary black hole systems I’ve ever come across,” said lead author, Associate Professor Miller-Jones from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR). “Like many black holes, it’s feeding on a nearby star, pulling gas away from the star and forming a disk of material that encircles the black hole and spirals towards it under gravity,” he said.
“What’s different in V404 Cygni is that we think the disk of material and the black hole are misaligned. This appears to be causing the inner part of the disk to wobble like a spinning top and fire jets out in different directions as it changes orientation.”
The international team of astronomers published their findings today in the journal Nature.
Astronomers recognized V404 Cygni as a black hole in 1989 when it released a big outburst of jets and radiation.
Back in 2015, it got the attention of astronomers around the world when it suddenly brightened for two weeks. The black hole began gobbling up material from a star that orbits it once every six days. As the material twisted into the black hole, it heated up enough to glow brightly.
“Everybody jumped on the outburst with whatever telescopes they could throw at it,” Professor Miller-Jones said.
“So we have this amazing observational coverage.”
The black hole is nine times more massive than the Sun and is eating a star 70% the size of the Sun.
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Black holes usually shoot jets straight from their poles. But V404 Cygni is spraying out jets in different directions at different times.
“The inner part of the accretion disk was precessing and effectively pulling the jets around with it,” Miller-Jones said in a statement. “You can think of it like the wobble of a spinning top as it slows down – only in this case, the wobble is caused by Einstein’s theory of general relativity.”
The wobble is so intense that the usual method of observing black holes was useless, explained Alex Tetarenko, a recent Ph.D. graduate from the University of Alberta and currently an East Asian Observatory Fellow working in Hawaii.
Instead, astronomers had to take 103 separate snaps of around 70 seconds and then stitch them together into a movie.
Now, astronomers are eager to understand and watch jets evolve in real time.
Astronomers based the study on observations from the Very Long Baseline Array. That’s a continent-sized radio telescope comprised of 10 dishes across the U.S., from the Caribbean’s Virgin Islands to Hawaii.
Thumbnail image: An artist’s impression of jet ejections in V404 Cygni. Credit: ICRAR