Researchers have identified the physical conditions that allow supermassive black holes to consume matter while simultaneously launching high-speed plasma jets. By observing galaxy 3C 120, a team led by Tohoku University and Nagoya City University discovered that a transition between a cold accretion disk and a hot plasma flow near the black hole enables the formation of these relativistic jets.
Mapping the 3C 120 environment
The mystery of how black holes feed without stifling their own jets has persisted because standard physics predicts that rapid accretion should form a cold, flat disk that blocks jet formation. As reported by Asia Research News, the research team resolved this by using the X-Ray Imaging and Spectroscopy Mission (XRISM) alongside a global network of radio and millimeter telescopes.
The data indicates that the cold accretion disk in 3C 120 terminates at approximately 20 times the black hole’s radius. Beyond this boundary, the matter transitions into a hot plasma flow reaching hundreds of millions of degrees. Associate Professor Hirofumi Noda noted that by observing the same black hole with both X-ray and radio instruments, the team could connect the hot plasma environment directly to the emergence of the jet.
Correlating accretion flares and radio bursts
While 3C 120 provides a window into jet formation, other systems offer different insights into how black holes process matter. Astronomers studying the galaxy NGC 1275, located in the Perseus Cluster, have observed a lag between X-ray flares and radio jet emissions.
According to Space and The Daily Galaxy, a team led by Sarah Ketchum of the University of Michigan tracked a record X-ray flare from NGC 1275 in February 2023. The flare, which doubled the brightness of the galaxy’s active nucleus, was followed by radio jet activity approximately 300 days later. Researchers ruled out a tidal disruption event—where a star is torn apart by gravity—as the cause, concluding instead that the flare resulted from a sudden spike in the black hole’s accretion rate.
Studying the mechanics of magnetic fields
The hot plasma flow identified in 3C 120 is essential for the accumulation of magnetic fields. These fields are theorized to extract rotational energy from the black hole, channeling it into the powerful jets observed by the Global Millimeter VLBI Array and the East Asian VLBI Network.
The team behind the 3C 120 study, whose findings were published in Astrophysical Journal Letters on October 19, 2026, is now applying these methods to more massive black holes. By comparing these observations with computer simulations, researchers aim to determine how matter, magnetic fields, and black hole rotation interact to influence the evolution of galaxies.
Frequently asked questions about black hole feeding
Why do some black holes launch jets while others do not? The formation of a relativistic jet depends on the environment near the black hole. Observations of 3C 120 show that a hot plasma flow—rather than just a cold accretion disk—allows magnetic fields to accumulate and channel energy into jets.
How do scientists measure the distance of an accretion disk? Researchers use X-ray spectroscopy to detect iron emission lines. The shape of these lines is distorted by Einstein’s general relativity, which allows scientists to calculate how close the accretion disk extends toward the black hole’s event horizon.
What is the connection between X-ray flares and radio jets? In systems like NGC 1275, researchers have observed a delay of roughly 300 days between a surge in X-ray brightness and the appearance of radio jets. This suggests a causal link where an increase in the matter being consumed leads to a subsequent "burp" of plasma energy.
Did you know? The black hole in NGC 1275 is estimated to be between 100 million and 1 billion times the mass of the sun, making it one of the most significant subjects for studying how active galactic nuclei impact their host clusters.
Pro tip: For those interested in the technical data behind these observations, the team’s pre-peer-review research is available on the arXiv repository.