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A black hole does not simply vacuum up everything around it. Most of the time, even a supermassive black hole — an object millions or billions of times heavier than the sun — can sit quietly at the center of a galaxy. It grows only when gas loses enough energy to spiral inward.
As that gas gathers into a fast-spinning disk, friction heats it until it glows intensely. Some of the material falls into the black hole. Some gets blasted back into space through powerful jets, which can heat the surrounding galaxy and slow the formation of new stars.
That creates an apparent contradiction. By heating and pushing away nearby gas, an active black hole should cut off its own food supply. Yet many supermassive black holes continue feeding for long periods. Astronomers have long suspected that some of the expelled or heated gas eventually cools, forms narrow filaments and falls back toward the center. However, they had struggled to see how those distant streams connected to the black hole’s immediate surroundings — until now.
New maps from the James Webb Space Telescope (JWST) now show the clearest connection yet between one of those filaments and the disk surrounding the black hole in NGC 4696, the giant galaxy at the center of the Centaurus Cluster, about 145 million light-years away. The finding fills in a crucial missing step in a feedback cycle that astronomers think helps black holes regulate both their own growth and the evolution of entire galaxies. The study in The Astrophysical Journal Letters describes a continuous pathway from galaxy-scale filaments to gas within roughly 100 parsecs of the black hole.
“What JWST is revealing is that black holes may be the ultimate cosmic recyclers,” said Julie Hlavacek-Larrondo, an astrophysicist at the Université de Montréal and the study’s lead author. “They release enormous amounts of energy that heat their surroundings, yet that same gas can later cool into thin filaments that fall back inward and feed the black hole again. We are finally seeing this self-sustaining cycle in action.”
From a Mysterious Swirl to a Galactic Supply Line
Hubble telescope images had already revealed an S-shaped swirl near the center of NGC 4696. But the images from Hubble could not reveal whether the glowing gas was rotating, falling inward or being blown outward.
Webb’s Near-Infrared Spectrograph watched the region for 7.7 hours and split the light into thousands of tiny spatial measurements. The resulting maps sampled structures about 10 parsecs, or 33 light-years, across — fine enough to trace gas within the region where the black hole’s gravity dominates.
The swirl proved to be a rotating, multiphase disk with a radius of roughly 120 parsecs, making it nearly 800 light-years across. The gas velocity changes by about 600 kilometers per second from one side of the disk to the other. A filament at least 350 parsecs long approaches from the west and meets the disk with matching velocities. Gas also grows more turbulent near the junction, as astronomers would expect if new material were joining the disk.
The small-scale radio jet points roughly north to south, while the filament stretches west. That makes a jet-driven outflow less likely. Computer simulations tailored to NGC 4696 produced a similar filament feeding a rotating central disk, strengthening the case for inflow.
“JWST is now showing us the final link of this closed loop,” said Helen Russell, an astrophysicist at the University of Nottingham and a study co-author. “The vast filamentary network of gas flows ultimately funnels gas down to a disk that fuels the black hole.”
A Recycling Loop Shaped by Magnetic Fields
The proposed cycle begins far outside the black hole. Jets inflate bubbles in the surrounding hot atmosphere. Gas around those bubbles cools and condenses, while magnetic fields stretch it into filaments. Magnetic tension can then rob the falling gas of some of its sideways motion, allowing it to plunge toward the galactic center. It does not fall straight into the black hole. First, it joins the circumnuclear disk, which acts as a reservoir and gateway to smaller scales.
Astronomers have been assembling this picture for years. A 2019 ALMA survey of 12 central cluster galaxies found enormous cold-gas reservoirs, typically spread through filaments extending for thousands of light-years, but could not resolve how most of them connected to the black hole. In 2024, ALMA observations of NGC 1275 in the Perseus Cluster showed molecular filaments converging on a roughly 100-light-year-wide nuclear disk.
The new Webb result reveals a cleaner connection in a second major cluster galaxy. It also detects both warm ionized gas and cooler molecular hydrogen in the disk, suggesting that the feeding pathway contains material at several temperatures and may be common rather than exceptional.
The observations do not follow gas all the way across the event horizon (the point of no return past which any matter or even light cannot escape the grasp of a black hole, falling inside), and the simulations still simplify how the black hole heats its surroundings. Nor does one nearby galaxy by itself explain how the earliest supermassive black holes grew so quickly.
But the study shows how a black hole can keep receiving fuel without simply defeating its own feedback: The jets interrupt feeding, yet also help create the conditions for the next meal.
This story originally appeared on ZME Science. Want to get smarter every day? Subscribe to our newsletter and stay ahead with the latest science news.
