Researchers have taken a major step toward understanding how black holes influence the universe by directly measuring the power of their jets. Using a network of radio telescopes spread across the globe, a team led by Curtin University captured detailed images that reveal just how energetic these jets can be. The findings support long-standing theories about the role black holes play in shaping the structure of galaxies.
The study, published in Nature Astronomy, focused on Cygnus X-1, a well-known system that includes the first confirmed black hole and a massive supergiant star. Scientists determined that the jets streaming from this black hole carry an energy output equal to about 10,000 Suns.
To make this measurement, the team relied on a widely spaced array of telescopes working together as one. This setup allowed them to watch how the jets were pushed and distorted by powerful winds coming from the nearby star as the black hole traveled along its orbit. The effect is similar to how strong gusts on Earth can bend a stream of water from a fountain.
Using Stellar Winds to Reveal Jet Strength
By calculating the strength of the star’s wind and tracking how much the jets were deflected, researchers were able to determine the jets’ power at a specific moment. This marks the first time scientists have directly measured the instantaneous energy of black hole jets rather than relying on long-term averages.
The team also measured the jets’ speed, finding that they travel at roughly half the speed of light, or about 150,000 kilometers per second. Determining this speed has been a challenge for scientists for many years.
The project was led by the Curtin Institute of Radio Astronomy (CIRA) and the Curtin node of the International Centre for Radio Astronomy Research (ICRAR), with contributions from the University of Oxford.
“Dancing Jets” Offer New Insight
Lead author Dr. Steve Prabu, who worked at CIRA during the study and is now at the University of Oxford, explained that the team used a sequence of images to track what he described as “dancing jets.” This term refers to the way the jets shift direction repeatedly as they are pushed by the supergiant star’s strong winds while both objects orbit each other.
Dr. Prabu said these observations reveal how much of the energy generated near a black hole is transferred into its surroundings, influencing the environment around it.
“A key finding from this research is that about 10 per cent of the energy released as matter falls in towards the black hole is carried away by the jets,” Dr. Prabu said.
“This is what scientists usually assume in large-scale simulated models of the Universe, but it has been hard to confirm by observation until now.”
Confirming Theories About Black Hole Physics
Co-author Professor James Miller-Jones, from CIRA and the Curtin node of ICRAR, noted that earlier techniques could only estimate jet power over extremely long periods, sometimes spanning thousands or millions of years. This made it difficult to directly compare jet energy with the X-ray emissions produced as matter falls into a black hole.
“And because our theories suggest that the physics around black holes is very similar, we can now use this measurement to anchor our understanding of jets, whether they are from black holes 10 or 10 million times the mass of the Sun,” Professor Miller-Jones said.
“With radio telescope projects such as the Square Kilometre Array Observatory currently under construction in Western Australia and South Africa, we expect to detect jets from black holes in millions of distant galaxies, and the anchor point provided by this new measurement will help calibrate their overall power output.
“Black hole jets provide an important source of feedback to the surrounding environment and are critical to understanding the evolution of galaxies.”
Other collaborators on the research included the University of Barcelona, the University of Wisconsin-Madison, the University of Lethbridge and the Institute of Space Science.