A rogue black hole shatters expectations with a standout tidal disruption event
In a discovery that reshapes our understanding of where supermassive black holes can lurk and how they behave, an international team led by Dr. Itai Sfaradi and Prof. Raffaella Margutti of the University of California, Berkeley, identified the first tidal disruption event (TDE) to produce bright, rapidly evolving radio signals far from the center of its host galaxy. Named AT 2024tvd, this event marks the fastest-changing radio emission ever recorded from a black hole swallowing a star and challenges the long-held assumption that dramatic radio outbursts occur primarily near galactic nuclei.
Key findings: fast radio evolution and distant location
The discovery reveals two distinct radio flares that evolve far more quickly than any previous TDE observed to date. This rapid variability indicates powerful outflows of material launched from the black hole’s vicinity, but not immediately after the stellar disruption. Instead, the data show a delayed evolution with at least two separate ejection events occurring months apart. This pattern suggests that black holes can “reawaken” after periods of apparent inactivity, emitting renewed energy long after the star is torn apart.
Compellingly, AT 2024tvd originated roughly 2,600 light-years (0.8 kiloparsecs) from the center of its host galaxy. Such a discovery demonstrates that supermassive black holes can exist and exert dramatic influence far from the galactic core, broadening our view of where these cosmic engines operate.
The role of radio astronomy in the breakthrough
The breakthrough was made possible through coordinated observations from several of the world’s premier radio telescopes. The Very Large Array (VLA) and ALMA contributed crucial data, while the Arcminute Microkelvin Imager Large Array (AMI-LA) in the United Kingdom, the Allen Telescope Array (ATA), and the Submillimeter Array (SMA) played vital roles in tracing the emission’s rapid evolution. Notably, AMI-LA, led by the Hebrew University of Jerusalem team, was instrumental in uncovering the fast-changing radio signals that define AT 2024tvd.
Interpretation: what this means for black hole physics
The observations suggest that the black hole’s surroundings undergo a complex sequence of events after the star’s destruction. The data favor models in which material is ejected in multiple, episodic outflows, potentially due to changes in accretion flow or magnetic processes near the event horizon. This challenges simpler pictures of TDEs and signals that the aftermath can be more dynamic and long-lived than previously thought.
Dr. Itai Sfaradi, the study’s lead author and a former student of Prof. Assaf Horesh, highlighted the significance: “This is truly extraordinary. 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.” Prof. Horesh added that seeing a former student lead such a discovery adds personal meaning and underlines Israel’s growing impact on international astrophysics.
Collaborations and publication
The international team spans institutions across the United States, Europe, and Israel, incorporating contributions from Prof. Paz Beniamini of the Open University of Israel, among others. The findings are published in The Astrophysical Journal Letters, illustrating how coordinated global efforts and state-of-the-art radio facilities can reveal unexpected cosmic phenomena.
Why AT 2024tvd matters for future research
AT 2024tvd opens a new window into the behavior of black holes in relatively tranquil galactic suburbs, suggesting that episodic activity may be more common than thought. Future surveys and targeted radio follow-ups will be essential to determine how often such distant, fast-evolving radio TDEs occur and what they reveal about black hole feeding and feedback on galactic environments.
Bottom line
AT 2024tvd stands as a landmark discovery—an unusual tidal disruption event that shines its brightest radio beacon far from the galaxy’s heart and does so with unprecedented speed. It confirms that the cosmic dance between stars and black holes can be more intricate and spectrally diverse than imagined.
