GRB 250702B: discovery of a gamma-ray burst from a black hole falling into a star

ABSTRACT Gamma-ray bursts are the most luminous electromagnetic events in the Universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess of a thousand seconds, referred to as ultra-long gamma-ray bursts. Here, we report the discovery of the longest gamma-ray burst ever seen with a $\sim$25 000 s gamma-ray duration, GRB 250702B, and characterize this event using data from four instruments in the InterPlanetary Network and the Monitor of All-sky X-ray Image. We find a hard spectrum, subsecond variability, and high total energy, which are only known to arise from ultrarelativistic jets powered by a rapidly spinning stellar-mass central engine. These properties and the extreme duration are together incompatible with all confirmed gamma-ray burst progenitors and nearly all models in the literature. This burst is naturally explained with the helium merger model, where a field binary ends when a black hole falls into a stripped star and proceeds to consume and explode it from within. Under this paradigm, GRB 250702B adds to the growing evidence that helium stars expand and that some ultra-long GRBs have similar evolutionary pathways as collapsars, stellar-mass gravitational wave sources, and potentially rare types of supernovae.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2025-11-14
DOI
https://doi.org/10.1093/mnras/staf2019
Citations
4
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
4.62

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article

GRB 250702B: discovery of a gamma-ray burst from a black hole falling into a star

Maia A. Williams, A. M. Laird, W. H. Cleveland, Jonathan Granot et al.
4 citations
Monthly Notices of the Royal Astronomical Society
Gamma-ray bursts and supernovae
4.62
article

GRB 250702B: discovery of a gamma-ray burst from a black hole falling into a star

Maia A. Williams, A. M. Laird, W. H. Cleveland, Jonathan Granot, Christian Aa. Diget, James DeLaunay, E. Bissaldi, Erin Kara, Oindabi Mukherjee, A. Tsvetkova, Sarah Dalessi, Suman Bala, Chris L. Fryer, Tyler Parsotan, Jordan Barber, A. Ridnaia, Carolyn Kierans, L. Scotton, Ramandeep Gill, O. J. Roberts, S. Lesage, V. Ashley Villar, C. Wilson‐Hodge, D. Frederiks, A. Trigg, P. Vereš, D. J. Lawrence, Joshua Wood, R. Hamburg, D. Svinkin, Megan Masterson, P. N. Bhat, J. Goldsten, Gavin P. Lamb, Sophie E. D. Abrahams, D. Kocevski, Eliza Neights, Alexander D. Hall-Smith, Michela Negro, Christian Malacaria, M. Ulanov, C. M. Hui, A. Goldstein, Boyan A. Hristov, A. Lysenko, Y. Kawakubo, Paz Beniamini, B. Mailyan, Michael Briggs, S. Ronchini, Eric Burns, Davide Depalo, M. Giles, Aldana Holzmann Airasca, Ryan Seeb
article en
4 citations

Abstract

ABSTRACT Gamma-ray bursts are the most luminous electromagnetic events in the Universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minutes. A rare subset of these events have durations in excess of a thousand seconds, referred to as ultra-long gamma-ray bursts. Here, we report the discovery of the longest gamma-ray burst ever seen with a $\sim$25 000 s gamma-ray duration, GRB 250702B, and characterize this event using data from four instruments in the InterPlanetary Network and the Monitor of All-sky X-ray Image. We find a hard spectrum, subsecond variability, and high total energy, which are only known to arise from ultrarelativistic jets powered by a rapidly spinning stellar-mass central engine. These properties and the extreme duration are together incompatible with all confirmed gamma-ray burst progenitors and nearly all models in the literature. This burst is naturally explained with the helium merger model, where a field binary ends when a black hole falls into a stripped star and proceeds to consume and explode it from within. Under this paradigm, GRB 250702B adds to the growing evidence that helium stars expand and that some ultra-long GRBs have similar evolutionary pathways as collapsars, stellar-mass gravitational wave sources, and potentially rare types of supernovae.

Monthly Notices of the Royal Astronomical SocietyVol. 545(2)
Florida Institute of Technology (US), Northwestern University (US), Louisiana State University (US), Marshall Space Flight Center (US), Goddard Space Flight Center (US), Pennsylvania State University (US), Aoyama Gakuin University (JP), Universities Space Research Association (US), Los Alamos National Laboratory (US), Open University of Israel (IL), University of Trento (IT), George Washington University (US), Brown University (US), Astronomical Observatory of Rome (IT), Johns Hopkins University Applied Physics Laboratory (US), Max Planck Institute for Extraterrestrial Physics (DE), National Space Science and Technology Center (US), Istituto Nazionale di Fisica Nucleare, Sezione di Bari (IT), Center for Astrophysics Harvard & Smithsonian (US), Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari (IT), Gran Sasso Science Institute (IT), The NSF AI Institute for Artificial Intelligence and Fundamental Interactions (US), Deleted Institution, University of York (GB), Liverpool John Moores University (GB), Massachusetts Institute of Technology (US), Polytechnic University of Bari (IT), University of Alabama in Huntsville (US), Universidad Nacional Autónoma de México (MX), Ioffe Institute (RU)
National Aeronautics and Space Administration, Oak Ridge Associated Universities, Johns Hopkins University, United States-Israel Binational Science Foundation, Nuclear Safety and Security Commission, Ioffe Institute, Jet Propulsion Laboratory, Marshall Space Flight Center, Office of STEM Engagement
Openalex Percentile: Top 5%
Gamma-ray bursts and supernovae
4.62
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