General information
GRB 260727A was a bright, long gamma-ray burst triggered by SVOM/ECLAIRs at 2026-07-27 00:22:02 UTC and also detected by SVOM/GRM, AstroSat/CZTI, Glowbug, and Konus-Wind. SVOM/EP-FXT later found an uncatalogued X-ray source at RA 331.7702 deg, Dec +74.5296 deg with a 10 arcsec 90% confidence error radius.
Wavelength coverage
- Gamma-ray: SVOM/ECLAIRs, SVOM/GRM, AstroSat/CZTI, AstroSat/Veto, Glowbug, and Konus-Wind detected the burst; reported durations range from about 20 s to 53 s depending on band/instrument.
- X-ray: SVOM/EP-FXT began follow-up about 5.09 hr after trigger and detected an uncatalogued 0.5-10 keV source with flux 2.65 (+0.55, -0.35) x 10^-12 erg/s/cm2.
- Optical/NIR: LCO, Kilonova-Catcher, GOTO, RAPAS, WINTER, Liverpool Telescope, AbAO, and SAO RAS reported no optical/NIR candidate, with limits including r > 22.17, i > 22.05, and Rc > 22.9.
Bands with no observations mentioned: radio, submillimeter, TeV, neutrino, gravitational wave.
Lightcurve and spectrum
- SVOM/ECLAIRs reported 41 alerts; the best image trigger had SNR 111.24 in 8-120 keV over 81.92 s starting at 2026-07-27 00:21:34 UTC.
- AstroSat/CZTI measured T90 = 20 (+3, -1) s in 20-200 keV, and the Veto detector measured T90 = 20 (+2, -3) s in 100-500 keV.
- Glowbug reported onset at 2026-07-27 00:21:57.592 UTC, duration 22.5 s, and total significance about 24.2 sigma.
- Konus-Wind reported a multi-peaked profile lasting about 30 s with emission up to about 300 keV, fluence 1.15e-5 erg/cm2, 64-ms peak flux 1.61e-6 erg/cm2/s, cutoff power-law alpha = -0.20, and Ep = 85 keV.
- SVOM/GRM measured T90 = 53 +3/-2 s in 15-5000 keV, fit T0-3 to T0+70 s with a cutoff power law, found index -0.64 +/- 0.09 and Epeak 81.7 +3.0/-2.7 keV, and measured 10-1000 keV fluence (1.352 +0.034/-0.032)E-05 erg/cm2.
- EP-FXT fit the X-ray source with an absorbed power law with photon index 2.61 +/- 0.07 and Galactic NH = (0.55 +/- 0.10) x 10^22 cm^-2.
Redshift
What’s special vs typical
GRB 260727A stands out as a bright, long, multi-instrument gamma-ray detection with a reported uncatalogued X-ray source, but the provided facts do not include an optical/NIR counterpart or redshift.