Extract from ABC News
In 2019, the Event Horizon Telescope made history when it captured the very first image of a supermassive black hole in the M87 galaxy.
Now, it has zoomed in on a second supermassive black hole, this time in the centre of a galaxy called Centaurus A.
Key points:
- The Event Horizon Telescope has captured images of a supermassive black hole in a nearby galaxy
- The images reveal plasma being launched from the black hole in extraordinary detail
- The jet's features are similar to those seen in another supermassive black holes, indicating that they are driven by similar processes
The new images capture a fiery jet of super-hot gas being spat out from the heart of the galaxy, allowing astronomers to pinpoint the location of its supermassive black hole.
The findings, published today in Nature Astronomy, could give clues about how these mysterious cosmic jets are generated.
“This has been seen before, but never quite so clearly,” said study co-author Phil Edwards, an astronomer at the CSIRO.
Chasing black holes
Black holes are the binge-eaters of the cosmos, devouring everything that gets trapped in their gravitational grip.
While low mass or stellar black holes form when massive stars collapse then explode in a supernova, supermassive black holes form in the centre of galaxies.
These behemoths contain somewhere between a million and a billion times more mass than their stellar counterparts.
In 2019, the EHT caught a glimpse of the supermassive black hole at the heart of the M87 galaxy around 53 million light-years from Earth.
This remarkable first image showed a bright, swirling disc of gas being pulled over the black hole's event horizon – the point where even light cannot escape – by the object’s monstrous gravitational force.
But at the last moment, some gas particles manage to escape the jaws of these cosmic monsters and are instead blown far into space.
"We see these as jets of plasma being accelerated at speeds very close to the speed of light away from the supermassive black hole," Dr Edwards said.
Peering into the heart of a black hole
Dr Edwards and his colleagues aimed the Event Horizon Telescope – an network of eight radio telescopes spanning the globe – at Centaurus A.
At a mere 12 million light-years away, Centaurus A was an ideal candidate for getting a close-up look at a supermassive black hole.
With a mass of 55 million Suns, Centaurus A's supermassive black hole is a fraction the size of M87’s, which has a mass of six-and-a-half-billion Suns.
But it is much more massive than Sagittarius A, the supermassive black hole in the middle of our home galaxy the Milky Way, which is around 4 million Suns.
The researchers could zoom in on Centaurus A's black hole and see structures that were less than a light-day wide. To put that in perspective, one light-day is the distance of three return trips from the Sun to Neptune.
This new observation was at a resolution 16 times sharper than previous ones.
The relatively fine-scale observations allowed the team to peer deep into the intricate structure of the jet blasting from the black hole, which flings gas more than a million light-years into space.
Something that stood out about this energetic cone of gas was its hollow centre and unusually bright edges.
These glowing features were remarkably similar to those seen in jets produced by other supermassive black holes, including the one within M87.
The finding suggests black holes are governed by similar processes regardless of their size.
“The physics is the same. It’s just being seen on quite different mass and size scales,” Dr Edwards said.
Understanding the inner workings of jets
The new images capture the jet processes in super-sharp detail, said Tamara Davies, an astrophysicist at the University of Queensland.
“It shows the super-energetic gas that’s expelled in jets from the poles of the black hole,” said Professor Davies, who was not involved in the study.
James Miller-Jones, who studies jet physics at Curtin University, said the findings were an important step in figuring out how supermassive black holes generate their massive jets.
“Characterising the detailed properties of the jets is important for understanding how they work, and the outsize influence that they have on their surroundings,” said Professor Miller-Jones, who was also not involved in the study.
The next step could involve taking a deeper look at the features of these jets, he added.
“Future observations could potentially track the motions and changes in the jets over time, better determining how they are launched and accelerated.”
No comments:
Post a Comment