In a study published in Nature Astronomy, a group of researchers from the University of Warwick has discovered that black holes do not just consume matter, but rather manage it, choosing whether to blast it into space as high-speed jets or sweep it away in vast winds.
This artist’s impression shows how the distant quasar P172+18 and its radio jets may have looked. To date (early 2021), this is the most distant quasar with radio jets ever found and it was studied with the help of ESO’s Very Large Telescope. It is so distant that light from it has travelled for about 13 billion years to reach us: we see it as it was when the Universe was only about 780 million years old. Image Credit: ESO/M. Kornmesser
It is commonly believed that anything that approaches a black hole is permanently consumed. However, prior to reaching the event horizon (the definitive point of no return), incoming matter creates a heated, rotating accretion disk surrounding the black hole. Surprisingly, substantial amounts of material from this disk are ejected back into space.
Black holes release matter from their accretion disks through two primary outflows:
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Relativistic jets: These are narrow, high-speed streams of plasma launched from the black hole’s poles, traveling at nearly the speed of light. They're powered by intense magnetic fields and the black hole’s rotation.
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X-ray winds: These are broader, slower-moving flows of highly ionized gas that are pushed out from the surface of the accretion disk. They're driven by a combination of radiation pressure and magnetic forces.
Both mechanisms play a key role in how black holes interact with and influence their surrounding environments.
The occurrence of these two distinct outflows, along with the reasons behind them and their potential connection, has long been a significant puzzle within the field of astrophysics.
A Tug-of-War in Space
Scientists have provided the first clear observational evidence that these two types of outflows are mutually exclusive. When one is active, the other disappears, suggesting that black holes cannot produce both relativistic jets and X-ray winds at the same time.
We’re seeing what could be described as an energetic tug-of-war inside the black hole’s accretion flow. When the black hole fires off a high-speed plasma jet, the X-ray wind dies down, and when the wind starts up again, the jet vanishes. This tells us something fundamental about how black holes regulate their energy output and interact with their surroundings.
Dr. Jiachen Jiang, Study Author and Teaching Fellow, University of Warwick
The research team concentrated on the black hole system 4U 1630−472, which possesses a mass approximately ten times greater than that of our Sun, and experiences periodic outbursts as it consumes material from a neighboring companion star.
By utilizing data from NASA’s NICER X-ray telescope, located on the International Space Station, along with South Africa’s MeerKAT radio telescope, the scientists observed the black hole over a duration of three years. The findings indicated that the black hole did not generate strong winds and powerful jets at the same time; however, the accretion disk and the volume of incoming material remained stable.
Our observations provide clear evidence that black hole binary systems switch between powerful jets and energetic winds – never producing both simultaneously – highlighting the complex interplay and competition between different forms of black hole outflows.
Dr. Zuobin Zhang, Study First Author and Postdoctoral Research Assistant, Department of Physics, University of Oxford
A Black Hole in Balance
The oscillating behavior exhibited by the black hole indicates a self-regulating mechanism, wherein winds and jets vie for the same energy or mass resources. Notably, both forms of outflows were observed to transport similar quantities of mass and energy, implying that although the nature of the outflow varies, the overall outflow rate remains approximately stable.
The study calls into question several long-standing beliefs regarding the powering of outflows. It suggests that the transition between winds and jets is not merely influenced by fluctuations in the amount of material being accreted by the black hole, but may also be contingent upon the magnetic field arrangement within the disk, a crucial element in determining how energy is discharged.
In summary, black holes do not merely consume matter; they also regulate it, choosing whether to expel it into space as a concentrated jet or to disperse it in extensive winds. The equilibrium between winds and jets is essential in controlling the growth of black holes, the formation of stars in adjacent areas, and the evolution of entire galaxies. This "cosmic seesaw" provides a significant new perspective on how these mysterious entities influence the universe.
Journal Reference:
Zhang, Z., et al. (2026) Evidence of mutually exclusive outflow forms from a black hole X-ray binary. Nature Astronomy. DOI: 10.1038/s41550-025-02753-x. https://www.nature.com/articles/s41550-025-02753-x