Hubble spotted a rare off-center black hole shredding a star, revealing the first optical discovery of a wandering supermassive black hole.
Astronomers using NASA telescopes have made a dramatic discovery that sounds like something from a science fiction film: a hidden black hole dubbed “Space Jaws.”
Located 600 million light-years away, this invisible giant lies in the dark space between stars, quietly consuming any star that drifts too close. Its presence was revealed through a newly identified tidal disruption event (TDE), in which a star was torn apart and devoured, releasing a powerful burst of radiation. TDEs offer valuable insight into black hole behavior, helping scientists understand the extreme conditions that generate energetic jets and winds during such events. These violent encounters appear as bright flashes in telescope observations.
The newly observed TDE, named AT2024tvd, helped astronomers identify a roaming supermassive black hole using data from NASA’s Hubble Space Telescope. Additional observations from NASA’s Chandra X-ray Observatory and the NRAO’s Very Large Array also confirmed that the black hole is located away from the galaxy’s center.
The paper was recently published in The Astrophysical Journal Letters.
Surprisingly, this black hole, with a mass of one million suns, is not located at the center of its host galaxy, where supermassive black holes are usually found actively consuming nearby material. Among the roughly 100 tidal disruption events (TDEs) detected by optical sky surveys, this is the first time one has been linked to a black hole positioned away from a galaxy’s core. All other known TDEs have been tied to central black holes.
At the galaxy’s center, a different and much larger supermassive black hole resides, with a mass of 100 million suns. Thanks to Hubble’s precise imaging, astronomers determined that the TDE occurred just 2,600 light-years from this central black hole—a distance that is only one-tenth of the span between our Sun and the Milky Way’s central black hole.
This larger black hole is classified as an active galactic nucleus because it emits energy as it pulls in surrounding gas. Although both black holes exist within the same galaxy, they are not gravitationally bound to each other as a binary system. The smaller black hole could one day drift toward the center and merge with the larger one, but for now, they remain too far apart to be connected by gravity.
A TDE happens when an infalling star is stretched or “spaghettified” by a black hole’s immense gravitational tidal forces. The shredded stellar remnants are pulled into a circular orbit around the black hole. This generates shocks and outflows with high temperatures that can be seen in ultraviolet and visible light.
“AT2024tvd is the first offset TDE captured by optical sky surveys, and it opens up the entire possibility of uncovering this elusive population of wandering black holes with future sky surveys,” said lead study author Yuhan Yao of the University of California at Berkeley. “Right now, theorists haven’t given much attention to offset TDEs. “I think this discovery will motivate scientists to look for more examples of this type of event.”
A Flash in the Night
The star-snacking black hole gave itself away when several ground-based sky survey telescopes observed a flare as bright as a supernova. But unlike a supernova, astronomers know that this came from a black hole snacking on a star because the flare was very hot, and showed broad emission lines of hydrogen, helium, carbon, nitrogen, and silicon. The Zwicky Transient Facility at Caltech’s Palomar Observatory, with its 1.2-meter telescope that surveys the entire northern sky every two days, first observed the event.
“Tidal disruption events hold great promise for illuminating the presence of massive black holes that we would otherwise not be able to detect,” said Ryan Chornock, associate adjunct professor at UC Berkeley and a member of the ZTF team. “Theorists have predicted that a population of massive black holes located away from the centers of galaxies must exist, but now we can use TDEs to find them.”
The flare was seemingly offset from the center of a bright massive galaxy as cataloged by Pan-STARRS (Panoramic Survey Telescope and Rapid Response System), the Sloan Digital Sky Survey, and the DESI Legacy Imaging Survey. To better determine that it was not at the galactic center, Yao’s team used NASA’s Chandra X-ray Observatory to confirm that X-rays from the flare site were also offset.
It took the resolving power of Hubble to settle any uncertainties. Hubble’s sensitivity to ultraviolet light also allows it to pinpoint the location of the TDE, which is much bluer than the rest of the galaxy.
Origin Unknown
The black hole responsible for the TDE is prowling inside the bulge of the massive galaxy. The black hole only becomes apparent every few tens of thousands of years when it “burps” from capturing a star, and then it goes quiet again until its next meal comes along.
How did the black hole get off-center? Previous theoretical studies have shown that black holes can be ejected out of the centers of galaxies because of three-body interactions, where the lowest-mass member gets kicked out. This may be the case here, given the stealthy black hole’s close proximity to the central black hole. “If the black hole went through a triple interaction with two other black holes in the galaxy’s core, it can still remain bound to the galaxy, orbiting around the central region,“ said Yao.
An alternative explanation is that the black hole is the surviving remnant of a smaller galaxy that merged with the host galaxy more than 1 billion years ago. If that is the case, the black hole might eventually spiral in to merge with the central active black hole sometime in the very far future. So at present, astronomers don’t know if it’s coming or going.
Erica Hammerstein, another UC Berkeley postdoctoral researcher, scrutinized the Hubble images as part of the study, but did not find any evidence of a past galaxy merger. But she explained, “There is already good evidence that galaxy mergers enhance TDE rates, but the presence of a second black hole in AT2024tvd’s host galaxy means that at some point in this galaxy’s past, a merger must have happened.”
Specialized for different kinds of light, observatories like Hubble and Chandra work together to pinpoint and better understand fleeting events like these. Future telescopes that will also be optimized for capturing transient events like this one include the National Science Foundation’s Vera C. Rubin Observatory and NASA’s upcoming Nancy Grace Roman Space Telescope. They will provide more opportunities for follow-up Hubble observations to zero in on a transient’s exact location.
Reference: “A Massive Black Hole 0.8 kpc from the Host Nucleus Revealed by the Offset Tidal Disruption Event AT2024tvd” by Yuhan Yao, Ryan Chornock, Charlotte Ward, Erica Hammerstein, Itai Sfaradi, Raffaella Margutti, Luke Zoltan Kelley, Wenbin Lu, Chang Liu, Jacob Wise, Jesper Sollerman, Kate D. Alexander, Eric C. Bellm, Andrew J. Drake, Christoffer Fremling, Marat Gilfanov, Matthew J. Graham, Steven L. Groom, K. R. Hinds, S. R. Kulkarni, Adam A. Miller, James C. A. Miller-Jones, Matt Nicholl, Daniel A. Perley, Josiah Purdum, Vikram Ravi, R. Michael Rich, Nabeel Rehemtulla, Reed Riddle, Roger Smith, Robert Stein, Rashid Sunyaev, Sjoert van Velzen and Avery Wold, 30 May 2025, The Astrophysical Journal Letters.
DOI: 10.3847/2041-8213/add7de
Funding: ZTF is a public-private partnership, with equal support from the ZTF Partnership and from the U.S. National Science Foundation.
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1 Comment
Ignore the “artist’s concepts” and look at the actual image. Not comparable.