General information
GRB 260629A is a likely short gamma-ray burst first reported by Fermi/GBM at 2026-06-29 15:06:58 UT, localized to RA 146.1 deg, Dec 70.6 deg with a 10.5 deg statistical uncertainty. It was subsequently reported in prompt gamma-rays by AstroSat CZTI, GECAM-A, and SVOM/GRM.
Wavelength coverage
- Gamma-ray / hard X-ray: Fermi/GBM detected and localized the burst; AstroSat CZTI detected it in 20-200 keV and its veto detector in 100-500 keV; GECAM-A detected it in about 70-6000 keV; SVOM/GRM detected it in 15-5000 keV.
No observations are mentioned in optical, infrared, ultraviolet, soft X-ray, radio, neutrino, or gravitational-wave bands.
Lightcurve and spectrum
- Fermi/GBM reported a trigger time of 15:06:58 UT and classified the event as a likely short GRB.
- AstroSat CZTI measured a peak at 2026-06-29 15:06:59 UTC, a T90 of 0.89 (+0.45, -0.48) s from the cumulative CZT light curve, and a peak count rate of 108 (+70, -15) counts/s above background in combined CZT data.
- AstroSat CsI veto data showed a peak at 2026-06-29 15:06:59 UTC and a peak count rate of 378 (+65, -73) counts/s above background, but no reliable T90 due to 1 s binning.
- GECAM-A reported a single pulse with T90 = 3.20 (+1.13, -1.10) s in about 70-6000 keV.
- SVOM/GRM reported a single pulse with T90 = 1.20 (+1.55, -0.65) s in 15-5000 keV.
- SVOM/GRM fit the time-averaged spectrum from T0-1.0 to T0+2.0 s with a power law of index -1.89 (+0.24, -0.39), with 10-1000 keV fluence of (2.35 +0.42/-0.40)E-06 erg/cm^2.
Redshift
What’s special vs typical
- The burst is well confirmed across four gamma-ray instruments, providing consistent prompt-emission detections and multiple duration measurements.
- Within the provided reports, it remains a prompt-only short-GRB event without a reported counterpart, host, redshift, or multi-messenger association.