General information
GRB 260709A is a likely long gamma-ray burst first triggered and localized by Fermi/GBM at 2026-07-09 01:07:32 UT, with subsequent high-energy detections by GECAM-B, SVOM/GRM, and AstroSat CZTI.
Wavelength coverage
- Gamma-ray / hard X-ray: Fermi/GBM detected and localized the burst; GECAM-B observed it in about 70-6000 keV; SVOM/GRM observed it in 15-5000 keV; AstroSat CZTI detected it in 20-200 keV.
- Optical/UV: SVOM/ECLAIRs did not observe it because the Fermi/GBM position was about 119 degrees from the SVOM optical axis and outside the ECLAIRs field of view.
No observations are mentioned in X-ray afterglow, optical imaging/spectroscopy, infrared, radio, neutrino, or gravitational-wave bands.
Lightcurve and spectrum
- Fermi/GBM reported a likely long GRB at RA = 84.1 deg, Dec = 74.0 deg, with statistical uncertainty of 4.0 deg.
- GECAM-B reported several pulses, T90 = 56 +5/-4 s, a power-law index of -2.38 +/- 0.25, and fluence of (1.5 +0.5/-0.3)E-05 erg/cm^2 in 10-1000 keV from T0 - 5 to T0 + 50 s.
- SVOM/GRM reported multiple pulses, T90 = 63 +/- 9 s, a power-law index of -2.87 +0.16/-0.09, and fluence of (3.0 +1.0/-1.2)E-05 erg/cm^2 in 10-1000 keV from T0 - 25 to T0 + 25 s.
- AstroSat CZTI reported multiple peaks, the strongest at 2026-07-09 01:07:50.62 UTC, peak count rate 108 (+32, -14) counts/s above background, total counts 1034 (+278, -266), local mean background 207 (+2, -3) counts/s, and T90 = 26 (+10, -8) s.
Redshift
What’s special vs typical
AstroSat CZTI notes that the burst is relatively weak, so its CZTI T90 measurement has larger uncertainty than usual; otherwise the circulars describe a typical long, multi-pulse GRB with only high-energy detections reported.