A rare tidal disruption event exposed a massive wandering black hole about 30,000 light-years from its galaxy’s center.
A star was torn apart nearly 30,000 light-years from the center of a massive nearby galaxy, exposing a black hole where astronomers rarely see one. The unusually distant flare revealed an extremely rare “wandering” black hole and may change how scientists understand the movements of massive black holes after galaxies collide.
Astronomers at the University of North Carolina at Chapel Hill traced the discovery to a tidal disruption event, or TDE. These powerful flares occur when a star passes too close to a massive black hole, and gravity pulls it apart.
Such events are rare anywhere in a galaxy, occurring on average once every 100,000 years. Astronomers have detected more than 100 over the past decade, but almost all appeared at galactic centers, where the largest black holes are normally expected. TDE 2025abcr broke that pattern.
The flare appeared approximately 30,000 light-years from the center of its galaxy, making it the most distant offset yet recorded for a tidal disruption event discovered with visible light.
“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 PhD 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.”
A merger may have set it loose
The black hole that produced the flare is estimated to contain roughly one million times the mass of the Sun. It may have been stranded away from the center following a galaxy merger long ago. Another possibility is that gravitational encounters with other black holes near the galactic center pushed it outward.
Black holes produce no light of their own, so astronomers usually cannot detect these isolated objects directly. A rare tidal disruption event can briefly illuminate their location as material from a destroyed star falls toward them.
“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”
AI searches beyond galactic centers
Artificial intelligence played a key role in identifying the event. The researchers used tdescore, an AI classification tool developed by Robert Stein at the University of Maryland and NASA Goddard, to search enormous collections of telescope observations for promising tidal disruption event 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.”
After the system flagged the flare, the UNC-Chapel Hill researchers used the Southern Astrophysical Research (SOAR) Telescope in Chile to confirm that it was a tidal disruption event. UNC helped build the 4.1-meter telescope and continues to operate it through an international consortium.
“We confirmed the nature of this event using the SOAR telescope in Chile, which UNC is a founding partner of,” said Benjamin C. Kaiser, postdoctoral researcher in physics and astronomy at UNC-Chapel Hill. “SOAR allows us to rapidly follow up 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.”
Visible light could uncover many more
TDE 2025abcr provides the first strong evidence that ground-based visible-light telescopes can reliably reveal wandering black holes. That ability could create new opportunities to investigate how massive black holes form, grow, and travel through galaxies.
Astronomers currently find tens of tidal disruption events each year, mostly in the relatively nearby universe. Future observatories, including the NSF-DOE’s Vera C. Rubin Observatory and the UNC-Chapel Hill-designed and built Argus Array, could increase that number to hundreds or even thousands annually while detecting them across much greater distances.
These flares can reveal more than hidden black holes. They also provide information about the evolution of stars and galaxies and expose matter to gravitational conditions that cannot be reproduced on Earth. By releasing immense amounts of energy, tidal disruption events give astronomers a rare view of extreme physics in action.
Reference: “TDE 2025abcr: A Tidal Disruption Event in the Outskirts of a Massive Galaxy” by Robert Stein, Jonathan Carney, Charlotte Ward, Raffaella Margutti, Xander J. Hall, Itai Sfaradi, Igor Andreoni, Panos Charalampopoulos, Ryan Chornock, Suvi Gezari, Geoffrey Mo, Yuhan Yao, Akash Anumarlapudi, Eric C. Bellm, Joshua S. Bloom, Malte Busmann, Ilaria Caiazzo, S. Bradley Cenko, Matthew J. Graham, Steven L. Groom, Daniel Gruen, Erica Hammerstein, Benjamin C. Kaiser, Mansi M. Kasliwal, Brendan O’Connor, Antonella Palmese, Josiah Purdum, Jillian C. Rastinejad, Reed Riddle, Ben Rusholme, Jesper Sollerman, Jean J. Somalwar and Sylvain Veilleux, 27 July 2026, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/ae77f3
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