An article published in “The Astrophysical Journal Letters” reports the discovery of a supermassive black hole on the outskirts of its host galaxy WISEA J014656.04-152214.7, approximately 30,000 light-years from its center. A team of researchers found its traces thanks to a so-called tidal disruption event cataloged as TDE 2025abcr. Detected for the first time by the Zwicky Transient Facility (ZTF), thanks in part to a new artificial intelligence algorithm, the event was confirmed and studied for months in various electromagnetic bands using various instruments. This discovery supports the theory that wandering supermassive black holes can exist very distant from the center of a galaxy, where they normally reside.
The image (Courtesy Robert Stein et al. 2026 ApJL 1006 L57. All rights reserved) shows an archival image of the galaxy WISEA J014656.04-152214.7 and the location of the TDE 2025abcr event (above), as well as the same area imaged on December 14, 2025, with the tidal disruption event visible in the blue circle.
Black holes may not give telltale signs of their existence if there’s no material close enough to be influenced in some way. In the case of the galaxy WISEA J014656.04-152214.7, 750 million light-years from Earth, a sufficiently revealing influence could be the destruction of a star that has come too close to the black hole, resulting in the release of very intense electromagnetic emissions.
The Zwicky Transient Facility (ZTF) monitors the Northern Hemisphere sky from Palomar Observatory. Many transient events are recorded and must be analyzed to determine their nature. To identify the most sought-after transients, tdescore was developed, a system based on a machine learning algorithm trained to identify tidal disruption events. This free/open-source software, available under the MIT license, has become the primary means of identifying new events of this type.
In October 2025, the ZTF detected the event cataloged as TDE 2025abcr, which was recognized as a tidal disruption event by tdescore. Subsequently, various instruments, including NASA’s Swift Observatory, were used to monitor the evolution of that event.
In the reconstruction of this tidal disruption event, a star approached a black hole and was torn apart by its extremely intense gravity. Around 30 such events are detected each year, but this is the first time a supermassive black hole has been discovered thanks to it in the outskirts of its galaxy, making it particularly interesting.
The researchers’ reconstruction goes back to the history of the galaxy in which TDE 2025abcr was detected. Galaxies normally undergo multiple mergers, meaning that while each original galaxy has a supermassive black hole at its center, during a merger there are two of them. There are some possible consequences of galaxy mergers, and therefore different possible reasons why the supermassive black hole ended up outside the galaxy that formed.
One possibility is that a massive galaxy cannibalized the stars of a dwarf galaxy, leaving only the core with its supermassive black hole. If, however, a more conventional galaxy merger occurred, supermassive black holes can also merge, but the interplay of gravitational pulls may instead project one of the two toward the outskirts of the galaxy that formed. This type of dynamics can be even more complex if there are already two supermassive black holes and a new galaxy merger brings a third one, leading to interactions that can push one of them out of the newly formed galaxy.
Further observations could help determine the origin of this supermassive black hole. Its discovery confirms that wandering supermassive black holes exist; it remains to be seen whether they’re rare or common but difficult to detect because they’re isolated. New telescopes will aid astronomers in this type of investigation, which will also help improve models of galaxy evolution and extreme events such as tidal disruption.
