Nature of the repeating gamma-ray burst GRB 250702B
In plain words
In July 2025 a gamma-ray source in a distant galaxy, seen as it was roughly 8 billion years ago, flared three times over several hours, unlike any known burst.
Precise statement
GRB 250702B (host redshift estimated as $z \sim 1$) showed three gamma-ray episodes over several hours, preceded by an X-ray transient detected by Einstein Probe about $10\,\mathrm{hours}$ earlier. Determine the engine: a relativistic tidal disruption of a star by an intermediate-mass black hole, an ultra-long collapsar with prolonged fall-back, or another channel. Answer: an identification whose energy budget and timescales fit the light curve, afterglow and host.
What would settle it
A spectroscopic host redshift and late-time observations showing or excluding a supernova, combined with afterglow modeling and comparison to tidal-disruption fall-back rates.
Status in the literature
Unverified note
2025: JWST and ground-based imaging placed the source in a host galaxy at an estimated $z \sim 1$; relativistic tidal disruption by an intermediate-mass black hole and an unusual collapsar remain the leading candidates.