Overview
- GRB 250702B emitted for nearly seven hours with repeated activity, the longest gamma‑ray burst ever recorded after detections by space-based observatories triggered rapid global follow-up.
- Observations traced the burst to a massive, dust-rich host about 7–8 billion light-years away, where heavy obscuration hid optical light and left only infrared and high‑energy signals detectable.
- Afterglow modeling indicates a narrow relativistic jet aimed toward Earth, with material moving at roughly 99% of light speed as it pierced dense dust in the host galaxy.
- Researchers have not identified a single progenitor, evaluating scenarios from massive-star collapse to exotic stellar mergers or tidal disruption by a stellar- or intermediate‑mass black hole, with unusual X‑ray activity outside the main burst also reported.
- Separately, JWST confirmed a supernova tied to GRB 250314A at redshift ≃7.3—about 720–730 million years after the Big Bang—with properties resembling modern nearby supernovae, establishing the earliest-known example.