GRB 260307B

General information

GRB 260307B triggered SVOM/ECLAIRs at 2026-03-07T13:45:26 UTC, with a promptly identified uncatalogued SVOM/MXT X-ray source in the field and a sub-threshold but consistent Fermi/GBM targeted-search detection.

Wavelength coverage

Gamma-rays / hard X-rays: SVOM/ECLAIRs detection with refined temporal/spectral analysis; Fermi/GBM targeted-search detection.
X-rays: SVOM/MXT reports an uncatalogued X-ray source consistent with the GRB region.
Optical: multiple facilities report early non-detections/upper limits; a VT candidate was later rejected; a low-significance NOT z-band source was reported.
Radio: ATCA non-detections with 8 GHz upper limits at 0.9, 4.8, and 11 days. No observations were mentioned in near-IR, UV (distinct from optical u-band), sub-mm, or TeV bands.

Lightcurve and spectrum

Redshift

What’s special vs typical

GCN 44133: GRB 260307B: ATCA Radio Upper Limits

2026-03-27T18:33:22.765Z | rev 0

GCN 43953: GRB 260307B: SVOM/ECLAIRs refined analysis

2026-03-10T16:09:19.190Z | rev 0

GCN 43948: Fermi GBM Sub-Threshold Detection of GRB 260307B

2026-03-08T15:14:09.152Z | rev 0

GCN 43947: GRB 260307B: Mephisto optical upper limits

2026-03-08T13:15:21.346Z | rev 0

GCN 43946: GRB 260307B: possible NOT optical counterpart

2026-03-08T12:01:24.110Z | rev 0

GCN 43945: GRB 260307B: SVOM/VT upper limit with X band data analysis

2026-03-08T06:53:14.885Z | rev 0

GCN 43943: GRB260307B: GROWTH-India Telescope optical upper limit

2026-03-07T17:57:41.751Z | rev 0

GCN 43942: GRB 260307B: SVOM/VT optical candidate

2026-03-07T16:41:03.424Z | rev 0

GCN 43941: GRB 260307B: SVOM/C-GFT upper limit

2026-03-07T15:46:50.018Z | rev 0

GCN 43940: GRB 260307B: SVOM detection of a burst

2026-03-07T14:09:39.916Z | rev 0