GRB 250702BDE

GRB 250702B

GRB 250702B (circled in red), taken on 3 July with the VLT’s HAWK-I infrared camera
Event type	Gamma ray burst
Right ascension	18h 58m 45.565s
Declination	−7° 52′ 26.42″
Redshift	≲ 1
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GRB 250702BDE was a series of three distinct ultra-long extragalactic gamma-ray bursts (GRB) discovered by the Fermi Gamma-ray Space Telescope on July 2, 2025. GRB 250702B, the first event, is the longest duration gamma-ray burst ever discovered. The event consisted of three repeated GRB events (250702B, 250702D, and 250702E) lasting several hours from the same astronomical source, implying potential periodicity within the progenitor system. ^{[1] [2] [3] [4] [5]}

Discovery

It was initially detected by the Fermi Gamma-ray Space Telescope on July 2, 2025. About 10 hours earlier, the Einstein Probe had detected an associated X-ray transient. ^{[2] [3] [6]}

It was initially believed to have originated inside the Milky Way. A day after the initial detection, the Very Large Telescope showed the source to be extragalactic; this was later confirmed by the Hubble Space Telescope. ^{[3] [4]}

Origin

Characterized by three intensifying bursting events at integer multiple timescales, GRB 250702BDE is distinct from the gamma-ray burst population due to its duration and potential periodicity. Although its spectroscopic redshift is unknown, it is thought to lie at z ~ 1 due to the brightness of the event's host galaxy relative to the brightness of GRB hosts at higher redshifts. ^[1] The event was likely caused by a relativistic tidal disruption event between a stellar-mass star and an intermediate-mass black hole (IMBH) or an unusual collapsar, however the source remains enigmatic and may be further resolved with long-term observations. ^{[1] [7]}

Gallery

• 
  Artistic Representation of GRB 250702B

See also

• GRB 111209A, the second longest lasting GRB at 7 hours

References

1. Levan, Andrew J.; Martin-Carrillo, Antonio; Laskar, Tanmoy; Eyles-Ferris, Rob A. J.; Sneppen, Albert; Ravasio, Maria Edvige; Rastinejad, Jillian C.; Bright, Joe S.; Carotenuto, Francesco; Chrimes, Ashley A.; Corcoran, Gregory; Gompertz, Benjamin P.; Jonker, Peter G.; Lamb, Gavin P.; Malesani, Daniele B.; Saccardi, Andrea; Sánchez-Sierras, Javier; Schneider, Benjamin; Schulze, Steve; Tanvir, Nial R.; Vergani, Susanna D.; Watson, Darach; An, Jie; Bauer, Franz E.; Campana, Sergio; Cotter, Laura; van Dalen, Joyce N. D.; D’Elia, Valerio; De Pasquale, Massimiliano; de Ugarte Postigo, Antonio; Hartmann, Dieter H.; Hjorth, Jens; Izzo, Luca; Jakobsson, Páll; Kumar, Amit; Melandri, Andrea; O’Brien, Paul; Piranomonte, Silvia; Pugliese, Giovanna; Quirola-Vásquez, Jonathan; Starling, Rhaana; Tagliaferri, Gianpiero; Xu, Dong; Wortley, Makenzie E. (1 September 2025). "The Day-long, Repeating GRB 250702B: A Unique Extragalactic Transient". The Astrophysical Journal Letters. 990 (1): L28. Bibcode:2025ApJ...990L..28L. doi: 10.3847/2041-8213/adf8e1 .
2. "Gamma-ray burst explodes in an unusual pattern never seen before". Earth.com. Retrieved 2025-09-11.
3. Dublin, University College. "Unprecedented gamma-ray burst hints at rare black hole". phys.org. Retrieved 2025-09-11.
4. Robert Lea (2025-09-09). "Astronomers discover repeating gamma-ray burst 'unlike anything we have ever witnessed before' (video)". Space. Retrieved 2025-09-11.
5. [e-mail]. "Astronomers spot mysterious gamma-ray explosion, unlike any detected before". www.eso.org. Retrieved 2025-09-11.
6. "GCN - Circulars - 40906 - EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E". gcn.nasa.gov. Retrieved 2025-09-11.
7. Neights, Eliza; Burns, Eric; Fryer, Chris L.; Svinkin, Dmitry; Bala, Suman; Hamburg, Rachel; Gill, Ramandeep; Negro, Michela; Masterson, Megan (2025-09-26), GRB 250702B: Discovery of a Gamma-Ray Burst from a Black Hole Falling into a Star, arXiv, doi:10.48550/arXiv.2509.22792, arXiv:2509.22792, retrieved 2025-12-17

Preceded by GRB 111209A

Longest gamma-ray burst 2025 –