The tidal disruption event TDE 2025abcr revealed a black hole with an estimated mass of about a million solar masses, far from where supermassive black holes are expected to be found. An artificial intelligence tool tailored to search for events outside the centers of galaxies helped make the discovery
A star has been torn apart about 30 light-years from the center of a massive galaxy, revealing a black hole where astronomers rarely see such objects. The flare, which occurred unusually far from the center of the galaxy, could provide a rare glimpse of a "wandering" black hole and change our understanding of the motion of galaxies. Black holes Massive due to mergers between galaxies.
Astronomers at the University of North Carolina at Chapel Hill have determined that the flare was caused by a tidal disruption event (TDE). These powerful events occur when a star passes too close to a massive black hole. The differences in gravity acting on different parts of the star stretch it and eventually tear it apart. Some of the material heats up as it makes its way toward the black hole and emits intense radiation.
Flare far from the center of the galaxy
Tidal disruption events They are rare anywhere in the galaxy and occur, on average, about once every 100 years in a given galaxy. Astronomers have discovered more than a hundred such events in the past decade, but almost all have been observed in the centers of galaxies – where the largest black holes are usually found. TDE 2025abcr deviated from this pattern.
The flare appeared at a projected offset of about 9.3 kiloparsecs, or about 30 light-years, from the center of the host galaxy. According to the researchers, this is the largest offset yet recorded for a tidal disruption event detected in visible light.
"Almost all of the tidal disruption events we observed occurred at the center of a galaxy, exactly where we expect to find the largest black holes," said Jonathan Carney, a doctoral student in physics and astronomy at the university and co-author of the paper. "The event we discovered occurred tens of thousands of light-years from the center and revealed a massive black hole in a place where we would not normally expect to find it."
Did a galaxy merger leave it behind?
The mass of the black hole that created the flare is estimated to be about a million solar masses. For comparison, the mass of the black hole at the center of the host galaxy is estimated to be hundreds of millions of solar masses.
The distant black hole may have been pushed away from the center of the galaxy by a merger that occurred long ago. Another possibility is that gravitational encounters with other black holes in the central region pushed it outward.
The researchers also suggest that the black hole is not wandering alone, but rather resides at the center of a very faint dwarf galaxy, which was stripped of most of its stars and gas when it merged with the larger galaxy. Therefore, observations do not yet prove how the black hole arrived at its current location.
Black holes do not produce their own light, so astronomers have difficulty detecting isolated black holes that do not swallow significant amounts of matter. A tidal disruption event may briefly illuminate the location of such a black hole, as fragments of the torn star heat up as they pass into it.
"These events are essentially cosmic bulletin boards," said Igor Andreoni, a professor of physics and astronomy at the University of North Carolina. "They allow us to find black holes that would otherwise remain completely invisible. When we catch these events in action, we can study how massive black holes swallow material from a disrupted star."
The artificial intelligence searched outside the center
Artificial intelligence played an important role in identifying the event. The researchers used tdescore, a tool Machine learning Developed by Robert Stein of the University of Maryland and NASA's Goddard Space Flight Center. The tool scans large collections of telescopic observations and identifies events that may be tidal disruption events.
The version used in the study was specifically tailored to search for outbursts far from the centers of galaxies. In doing so, the researchers removed a common assumption that tidal disruption events should be searched primarily in the galactic nucleus.
"The event was identified as a promising candidate for a tidal disruption event using a classifier artificial intelligence "We specifically trained it to look for events far from the centers of galaxies," said Akash Anumralpoodi, a postdoctoral researcher in physics and astronomy. "Removing the assumption that these events only occur in the centers of galaxies allowed us to find a black hole that we might otherwise have missed. As astronomy enters the era of replica data, such AI tools will become increasingly important in the search for rare astronomical events."
After the system flagged the flare, the researchers usedSOAR telescope, which is 4.1 meters in diameter and is located in Chile, to confirm through follow-up observations that this is a tidal disruption event.
According to Benjamin Kaiser, a postdoctoral researcher and co-author of the study, the telescope allows the team to respond quickly to short-lived astronomical events, a capability that is expected to become even more important as new survey observatories begin to detect large numbers of transient events.
Rubin Observatory may find dozens of similar cases
TDE 2025abcr provides evidence that ground-based visible-light telescopes can detect massive black holes located far from the centers of galaxies. This possibility could open up a new avenue for studying the formation, growth, and motion of black holes in galaxy collisions and mergers.
Today, dozens of tidal disruption events are discovered every year, most of them in the relatively nearby universe. Future survey prospects, including Mitzpe Vera RubinThe Nancy Grace Roman Space Telescope and the planned Argus array could increase the number to hundreds or even thousands of events per year. The authors estimate that the Rubin Observatory alone could detect dozens of similar events with measurable offsets each year.
These flares don't just reveal hidden black holes. They provide information about the evolution of stars and galaxies, exposing material to extreme gravitational conditions that cannot be replicated on Earth. The enormous energy released in tidal disruption events gives astronomers a rare opportunity to observe extreme physics as it happens.
Questions and Answers
what is A wandering black hole? This is a massive black hole that is not located in the galactic nucleus, where large black holes are usually found. It may be displaced by galaxy mergers or gravitational encounters with other black holes.
How was TDE 2025abcr discovered? The black hole itself is invisible. It was discovered by radiation emitted when a star approached it, was torn apart by tidal forces, and some of its material heated up. An artificial intelligence tool identified the flare as a candidate for a tidal disruption event.
Why is the location of the event unusual? It occurred about 30 light-years from the center of the galaxy. Almost all tidal disruption events previously detected in visible light have been found near galactic nuclei.
Has it been proven that the black hole was kicked out of the center of the galaxy? No. That's one possibility, but it could also be in the remnant of a dwarf galaxy that was swallowed by a larger galaxy. Further observations will be needed to decide between the possibilities.
More on the subject on the science website
- Dust may betray supermassive black holes kicked out of galaxy centers
- A black hole probably ripped apart a massive star, creating an unprecedented cosmic flash
- Not everything was swallowed: Black hole system continued to eject material even after the outburst died down
- More than half a million galaxies in the picture: Rubin Observatory opens the COSMOS field to science
- The black hole at the center of the Milky Way isn't tearing everything apart.
The scientific article
Image caption: Artist's impression of a tidal disruption event: A star passes too close to a massive black hole, is torn apart, and its fragments heat up as they orbit the black hole. A relativistic jet may be emitted from the system. This is a general illustration and does not necessarily depict TDE 2025abcr. Credit: NRAO/AUI/NSF/NASA
ALT: Simulation of a tidal disruption event in which a massive black hole rips apart a star and launches a relativistic jet
Filename: wandering-black-hole-tde-2025abcr.jpg
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