New study reveals, for the first time, a tidal disruption event (TDE), where a black hole tears apart a star, occurring outside the center of a galaxy that produced exceptionally strong and rapidly evolving radio signals. This rare discovery shows that supermassive black holes can exist and remain active far from galactic cores, challenging current understanding of where such black holes reside and how they behave. The event’s delayed and powerful radio outbursts also suggest previously unknown processes in how black holes eject material over time.
An international team of astronomers, led by Dr. Itai Sfaradi and Prof. Raffaella Margutti of the University of California, Berkeley, with the participation of researchers from around the world, including Prof. Assaf Horesh from the Racah Institute of Physics at the Hebrew University of Jerusalem, has discovered the first tidal disruption event (TDE) producing bright radio emission outside the center of a galaxy.
The event, designated AT 2024tvd , revealed the fastest-evolving radio emission ever observed from a black-hole-driven stellar disruption.
“This is truly extraordinary,” said Dr. Itai Sfaradi, lead author of the study. “Never before have we seen such bright radio emission from a black hole tearing apart a star, away from a galaxy’s center, and evolving this fast. It changes how we think about black holes and their behavior.”
Dr. Sfaradi, who led the research, is a former graduate student of Prof. Assaf Horesh. “This is one of the fascinating discoveries I’ve been part of,” said Prof. Horesh. “The fact that it was led by my former student, Itai, makes it even more meaningful. It’s another scientific achievement that places Israel at the forefront of international astrophysics.”
A black hole far from home
Tidal disruption events occur when a star ventures too close to a massive black hole and is torn apart by its immense gravity.
In this exceptional case, however, the black hole was located about 2,600 light-years (0.8 kiloparsecs) from its host galaxy’s core, evidence that supermassive black holes can lurk in unexpected places.
The key role of radio observations
The discovery was made possible through high-quality observations from several of the world’s premier radio telescopes, including the Very Large Array (VLA), ALMA, ATA, SMA, and the Arcminute Microkelvin Imager Large Array (AMI-LA) in the UK.
The AMI observations, led by the Hebrew University team, were crucial in revealing the unusually rapid evolution of the radio emission — a hallmark of this event and a major clue to understanding its physical nature.
The data showed two distinct radio flares evolving faster than any TDE observed before. These results indicate that powerful outflows of material were launched from the vicinity of the black hole not immediately after the stellar destruction, but months later, suggesting delayed and complex processes in the aftermath of the disruption.
Detailed modeling points to at least two separate ejection events, months apart — clear evidence that black holes can episodically “reawaken” after periods of apparent inactivity.
The research was conducted in collaboration with scientists from institutions across the United States, Europe, and Israel, including Prof. Paz Beniamini of the Open University of Israel, and will be published in The Astrophysical Journal Letters.
The research paper titled “The First Radio-Bright Off-Nuclear TDE 2024tvd Reveals the Fastest-Evolving Double-Peaked Radio Emission” is now available in The Astrophysical Journal, and can be accessed at https://doi.org/10.48550/arXiv.2508.03807
Researchers:
Itai Sfaradi1,2, Raffaella Margutti1,3,2, Ryan Chornock1,2, Kate D. Alexander4, Brian D. Metzger5,6, Paz Beniamini7,8,9, Rodolfo Barniol Duran10, Yuhan Yao1,11,2, Assaf Horesh12, Wael Farah1,13,14, Edo Berger15, Nayana A.J.1,2, Yvette Cendes16,17, Tarraneh Eftekhari18, Rob Fender19, Noah Franz4, Dave A. Gree20, Erica Hammerstein1,2, Wenbin Lu1,21,2, Eli Wiston1,2, Yirmi Bernstein12, Joe Bright19, Collin T. Christy4, Luigi F. Cruz12, David R. DeBoer22,23, Walter W. Golay15, Adelle J. Goodwin24, Mark Gurwell15, Garrett K. Keating15, Tanmoy Laskar25, James C. A. Miller-Jones24, Alexander W. Pollak13, Ra,prasad Rao15, Andrew Siemion19,26,13,14,27,28, Sofia Z. Sheikh14,14, Nadav Shoval12, Sjoert Van Velzen29
Institutions:
- Department of Astronomy, University of California
- Berkeley Center for Multi-messenger, Research on Astrophysical Transients and Outreach (Multi-Raptor), University of California
- Department of Physics, University of California
- Department of Astronomy and Steward Observatory, University of Arizona
- Department of Physics and Columbia Astrophysics Laboratory, Columbia University
- Center for Computational Astrophysics, Flatiron Institute
- Department of Natural Sciences, The Open University of Israel
- Astrophysics Research Center of the Open University (ARCO), The Open University of Israel
- Department of Physics, The George Washington University
- Department of Physics and Astronomy, California State University
- Miller Institute for Basic Research in Science
- Racah Institute of Physics, The Hebrew University of Jerusalem
- SETI Institute
- Berkeley SETI Research Centre, University of California
- Center for Astrophysics, Harvard & Smithsonian
- Department of Physics, University of Oregon
- Institute for Fundamental Science, University of Oregon
- Center for Interdisciplinary Exploration and Research in Astronomy (CIERA) Northwestern University
- Astrophysics, Department of Physics, University of Oxford
- Astrophysics Group, Cavendish Laboratory
- Theoretical Astrophysics Center, University of California
- Radio Astronomy Laboratory, University of California
- Sub-department of Astrophysics, University of Oxford
- International Centre for Radio Astronomy Research – Curtin University
- Department of Physics & Astronomy, University of Utah
- Breakthrough Listen, Astrophysics, Department of Physics, The University of Oxford
- Department of Physics and Astronomy, University of Manchester
- University of Malta, Institute of Space Sciences and Astronomy
- Leiden Observatory, Leiden University
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