A team of astronomers at the University of North Carolina at Chapel Hill has observed an extremely rare “wandering” black hole located tens of thousands of light-years from the center of its galaxy. This finding could reshape scientists’ understanding of how massive black holes move through the universe after galaxies collide. The findings are published in The Astrophysical Journal Letters.
The discovery centers on a powerful cosmic flare known as a tidal disruption event, or TDE, which occurs when a star wanders too close to a massive black hole and is violently torn apart by gravity. Tidal disruption events anywhere in a galaxy are rare, occurring on average once every 100,000 years. While astronomers have identified more than a hundred of these events over the past decade, nearly all have been found at the centers of galaxies, where scientists expect the largest black holes to reside. But this newly discovered event, dubbed TDE 2025abcr, was different.
A flare far from home
Researchers found the flare approximately 30,000 light-years from the center of a massive nearby galaxy, the farthest offset ever observed for an optically discovered tidal disruption event.
“Almost every tidal disruption event we’ve ever observed has occurred at the center of a galaxy, right where we expect the biggest black holes to be,” said Jonathan Carney, co-author of the paper and Ph.D. student in physics and astronomy at UNC-Chapel Hill. “The tidal disruption event we discovered happened tens of thousands of light-years away from the center, revealing a massive black hole in a place we would not normally expect to find one. We know that wandering black holes exist in massive galaxies, but they are difficult to study because, with the exception of when they briefly disrupt a star, they produce no light.”
The black hole responsible for the flare is estimated to be roughly one million times the mass of the sun. Researchers believe it may have been left behind after two galaxies merged in the distant past, or possibly thrown outward through gravitational interactions with other black holes near the galaxy’s center.
Because black holes themselves emit no light, astronomers rely on rare events like TDEs to reveal their existence.
AI helped spot the signal
“These events are essentially cosmic billboards,” said Igor Andreoni, assistant professor of physics and astronomy at UNC-Chapel Hill. “They allow us to find black holes that would otherwise remain completely invisible. Catching these events in the act allows us to study how massive black holes eat material from a disrupted star.”
The discovery was made possible in part by artificial intelligence. Researchers used an AI classification tool called tdescore, developed by Robert Stein at the University of Maryland and NASA Goddard, to scan enormous amounts of telescope data and identify promising TDE candidates.
“This event was identified as a strong candidate tidal disruption event by an AI classifier that we specifically adapted to search for tidal disruption events away from galaxy centers,” said Akash Anumarlapudi, a postdoctoral researcher in physics and astronomy at UNC-Chapel Hill. “By removing the assumption that these events only happen in the galactic center, we were able to find a black hole that might have otherwise been missed. As astronomy enters its ‘big data’ era, AI tools like this one will become increasingly important in our research chasing rare astronomical events at Carolina.”
Ground telescopes open a path
Once the event was flagged, the Carolina team confirmed its nature using the Southern Astrophysical Research (SOAR) Telescope in Chile, a 4.1-meter telescope that UNC helped build and continues to operate as part of an international consortium.
“We confirmed the nature of this event using the SOAR telescope in Chile, which UNC is a founding partner in,” said Benjamin C. Kaiser, postdoctoral researcher in physics and astronomy at UNC-Chapel Hill. “SOAR allows us to rapidly follow up on these short-lived astronomical phenomena and positions UNC to study large numbers of them as next-generation survey telescopes like Rubin, Roman and UNC’s own Argus Array come online.”
Researchers say TDE 2025abcr provides the first strong evidence that astronomers can reliably discover wandering black holes using ground-based visible-light telescopes, opening the door to entirely new studies of how black holes form, grow and move throughout galaxies. Astronomers are expected to go from discovering tens of tidal disruption events per year in the relatively nearby universe to discovering many hundreds, if not thousands, per year at much greater distances due to the next generation of telescopes, such as the NSF–DOE’s Vera C. Rubin Observatory and the UNC-Chapel Hill–designed and built Argus Array.
Beyond helping scientists understand black holes, the research also sheds light on the life cycles of stars and galaxies and the extreme physics of the universe. Tidal disruption events release enormous amounts of energy and help astronomers study gravitational forces and matter under conditions impossible to recreate on Earth.
Publication details
Robert Stein et al, TDE 2025abcr: A Tidal Disruption Event in the Outskirts of a Massive Galaxy, The Astrophysical Journal Letters (2026). DOI: 10.3847/2041-8213/ae77f3
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University of North Carolina at Chapel Hill
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Astronomers identify one of the universe’s rarest black hole events (2026, July 27)
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