Three Black Holes, One Ancient Galaxy: Webb Finds a Cosmic Trio From 1.2 Billion Years After the Big Bang

Most galaxies are thought to host a single supermassive black hole at their centre. Now astronomers using the James Webb Space Telescope have found three — all actively feeding — inside one galaxy more than 12.5 billion light-years away, seen as it was just 1.2 billion years after the Big Bang, in what researchers describe as the first evidence of a triple active black hole system in the distant universe.

Illustration: A distant early galaxy hosting three glowing black holes, symbolizing the triple system found in J0148-4214.

What Happened

An international team led by the Max Planck Institute for Extraterrestrial Physics (MPE) studied the galaxy J0148-4214 with Webb's Near-Infrared Spectrograph (NIRSpec) in its Integral Field Unit mode, which records a spectrum at every point in the image rather than blending all the light together. The study, nicknamed BlackTHUNDER, was published in the journal Astronomy & Astrophysics, and its results were reported on 25 October 2026.

Earlier observations had shown the galaxy as hosting a single black hole. The new analysis told a different story. By reading the fingerprints of hydrogen gas moving at very high speeds near the galaxy's centre, the team found a pattern too complicated for one black hole. Using spectro-astrometry — tracking tiny shifts in where the light comes from — they separated the central signal into two black holes just 620 light-years apart in projection. A third turned up in the galaxy's outer region, about 5,500 light-years from the centre.

"This is the first evidence of three active black holes in a single galaxy in the distant Universe," said Hannah Übler, research group leader at MPE and lead author of the study. All three are actively accreting matter, pulling gas and dust inward through surrounding disks. The masses are strikingly different: the larger central black hole weighs approximately 80 million times the mass of the Sun, its smaller central companion about 600,000 Suns, and the outer black hole around 2 million Suns.

The team tested other explanations before settling on three black holes. Shocks, stellar winds, supernovae and unusually massive stars were all considered, but the spectral signatures favoured three accreting black holes. One detail stood out: the much smaller central black hole is feeding especially rapidly, apparently exceeding the conventional Eddington limit — the theoretical maximum rate at which a black hole is expected to gather matter. Researchers expect the inner pair to merge over the coming few hundred million years.

Background

The distance of J0148-4214 is itself part of the story. Its light has travelled for approximately 12.5 billion years to reach Earth, so astronomers see the galaxy as it was only about 1.2 billion years after the Big Bang. The expansion of the universe stretches that light toward longer, redder wavelengths; the team measured a redshift of z = 5.02, which pins down both the distance and the cosmic epoch being observed.

Why does a triple system matter? Supermassive black holes — millions to billions of times the Sun's mass — are found at the centres of most large galaxies today, including the Milky Way's Sagittarius A*. But how they grew so large so early in cosmic history remains one of astronomy's biggest puzzles. One leading idea is that galaxies collided frequently in the young universe, bringing their central black holes together until they merged into ever-larger ones. Finding three active black holes already sharing one galaxy just 1.2 billion years after the Big Bang suggests those bringing-together processes were remarkably efficient.

The technique matters as much as the result. Webb could not resolve the two central black holes as separate points of light — they are far too close together at such a distance. Instead, the team used spectro-astrometry to trace small positional changes in the spectral emissions, effectively separating sources that blur together in an ordinary image. Without that detailed view, two of the three black holes would probably never have been found — a hint that other "single" black holes in early galaxies may also be hiding companions.

Webb, launched in 2021 as a joint NASA, European Space Agency and Canadian Space Agency mission, was built to study the early universe in infrared light, which is exactly the light stretched redward from galaxies like J0148-4214. Its spectrographs have become workhorses for early-universe research, and this result adds to a run of discoveries — from unexpectedly massive early galaxies to the first directly imaged exoplanets — that keep revising the timeline of cosmic history.

Illustration: A gold space telescope with a hexagonal mirror array above Earth, symbolizing the James Webb Space Telescope that made the discovery.

Why It Matters

The discovery matters because it turns a theoretical expectation into observed evidence. Astronomers have long expected that galaxy mergers in the early universe should produce multiple black holes sharing a single system, on their way to merging. But catching three of them actively feeding at once, in a galaxy from the universe's first billion-plus years, is something else entirely. As Übler put it, the finding suggests that processes in the early universe were efficient at bringing massive black holes together, "setting the stage for the massive black hole mergers we expect to detect with future gravitational wave observatories."

That last point connects this distant galaxy to instruments being built today. When black holes merge, they send ripples through spacetime — gravitational waves — that future observatories, including the planned space-based LISA mission, hope to detect from merging supermassive black holes. Systems like J0148-4214 are the ancestors of those mergers: watching them now tells researchers what to expect, and how often such mergers should occur.

The result also sharpens the mystery of rapid black hole growth. The smaller central black hole, at only about 600,000 solar masses, is feeding above the Eddington limit — gathering matter faster than basic models predict. If small black holes could grow this fast in the early universe, it helps explain how billion-solar-mass giants existed when the universe was less than a billion years old, a puzzle that has challenged models since Webb began finding them.

Finally, the discovery is a reminder of how much remains hidden in existing data. J0148-4214 was already known; it took a new way of reading Webb's spectra to reveal that its "single" black hole was three. Astronomers now have reason to revisit other early galaxies with the same technique — and reason to suspect that the early universe was a far more crowded, violent place than the first Webb images suggested.

What Happens Next

The research team and others will now test the triple system further. Follow-up observations with Webb and ground-based telescopes could refine the masses, separations and feeding rates, and check whether the three objects show the variability expected of accreting black holes. Theorists, meanwhile, will model how such a system forms and how quickly the inner pair should spiral together and merge.

Broader surveys may turn up more triple systems. If J0148-4214 is not a freak — and the efficiency argument suggests it may not be — then spectro-astrometry applied to other early galaxies could reveal a population of multiple black holes in the young universe. That population would give researchers statistics, not just one example, to test models of black hole growth and galaxy assembly.

Longer term, the system points toward gravitational-wave astronomy's next frontier. The inner pair in J0148-4214, separated by 620 light-years, will take hundreds of millions of years to merge — far beyond any human timescale — but systems like it, at later stages, should produce the low-frequency gravitational waves that future space observatories are designed to hear. Each new multiple system found today helps predict the chorus those observatories will listen for.

For now, J0148-4214 stands as a record: the most distant triple active black hole system yet found, in a galaxy glimpsed from the dawn of time, where three cosmic giants were already feeding together while the universe was still in its infancy.

Illustration: A scientist studying colorful spectral patterns on screens, symbolizing the spectro-astrometry technique that separated the three black holes.

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FAQ

What exactly did astronomers find in galaxy J0148-4214?

Three actively feeding supermassive black holes in a single galaxy, seen as it was 1.2 billion years after the Big Bang. Two sit near the galaxy's centre, 620 light-years apart; the third lies about 5,500 light-years from the centre.

How far away is J0148-4214?

More than 12.5 billion light-years away. Its light has travelled for about 12.5 billion years, and its redshift of z = 5.02 confirms the distance and the early cosmic epoch.

How could Webb tell there were three black holes if it could not see them separately?

The team used Webb's NIRSpec instrument in Integral Field Unit mode plus spectro-astrometry: tracking tiny shifts in the position of hydrogen emission lines to separate sources blurred together in ordinary images.

Why is the smaller central black hole's feeding rate important?

At roughly 600,000 solar masses, it appears to be feeding above the Eddington limit, the theoretical maximum growth rate. That helps explain how black holes grew so large so early in the universe.

Will these black holes merge?

Researchers expect the inner pair to merge over the coming few hundred million years. Such mergers would eventually produce gravitational waves detectable by future observatories.

Sources

• Geek Slop, "James Webb Finds Three Black Holes In A Galaxy Near The Big Bang," October 2026 — MPE-led team, masses, separations, NIRSpec IFU, Eddington limit.
• The World Insiders, "Webb reveals three active black holes in a distant galaxy," October 2026 — Übler quote, inner-pair merger timescale, spectro-astrometry details.
• Europe Says, "Three giant black holes discovered in a galaxy from the dawn of time," October 2026 — redshift z = 5.02, 12.5 billion light-years, gravitational-wave context.
• Hayadan, "Webb discovered three black holes in an ancient galaxy," October 2026 — BlackTHUNDER study, Astronomy & Astrophysics, alternative explanations ruled out.