ICRAR
Artist’s illustration of the Cygnus X-1 binary system
For the first time, astronomers have been able to estimate the speed of a black hole’s jets: it is about 150 thousand kilometers per second, or about half the speed of light.
Astronomers have long been fascinated by the powerful jets emanating from black holes, which result from gas and dust being drawn into the black hole’s gravitational well, forming a accretion disk where matter is accelerated to speeds close to the speed of light.
Although most of this material ends up fall slowly Towards the event horizon of the black hole, part of it spirals away from the poles, creating powerful jets that can be observed many light-years away.
In a recent study, a team of astrophysicists led by Curtin University used 18 years of high-resolution radioimaging data to study jets in the system Cygnus X-1the first confirmed binary system composed of a black hole and a supergiant star.
The images made it possible to measure the enormous power of these jets, equivalent to the energy production of 10 thousand suns. These findings confirm previous theories about how black holes shape the structure of the Universe.
The team, led by Steve Prabu e James Miller-Jonesrespectively adjunct associate professor and professor at the International Center for Radio Astronomy Research (ICRAR), at Curtin University, presented their results in a published in April in the journal Nature Astronomy.
To understand the power of the black hole’s jets, the team had to observe How are these disturbed? by the stellar wind coming from the massive star with which it shares the orbit.
To do this, it combined radio data from the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN), two networks of telescopes with stations spread around the world.
These combined observations created a more complete picture of the system, through a technique known as very long baseline interferometry, or VLBI.
This allowed the team to measure how far the black hole’s jets are whipped. as it orbits its stellar companionthus providing, for the first time, estimates of the power of these jets.
Also for the first time, the calculations made it possible to estimate the speed of the black hole’s jets, which rotated at around 150 thousand kilometers per secondor about half the speed of light.
These measurements allow us to understand what fraction of the energy released around black holes is probably deposited in the surrounding spaceultimately revealing how these objects shape the environments around them.
“One of the conclusions of the study is that around 10% of energy released when matter falls toward the black hole is transported by jets”, said Prabu, in a statement published on .
“This is what scientists usually assume in large-scale simulated models of the Universe, but so far It has been difficult to confirm by observation”, he highlights.
Miller-Jones adds that previous methods could only measure the average power of the jets over thousands to millions of yearspreventing rigorous comparisons with the X-ray emissions caused by falling matter:
“Since our theories suggest that the physics around black holes are very similar, we can now use this measurement as a starting point to understand the jets, whether they come from black holes with 10 or 10 million times the mass of the Sun”, notes Miller-Jones.
Black hole jets are an important source of feedback on the surrounding environment and are crucial for understanding the evolution of galaxies, the study authors note.
With radio telescope projects like the Square Kilometer Array Observatory, currently under construction in Western Australia and South Africa, the team now hopes to detect jets from black holes in millions of distant galaxies — and the reference point provided by this new measurement will help calibrate your total power.
