General information
GRB 260721A is reported as a long-duration gamma-ray burst detected in prompt emission by NuSTAR SINGS and independently by Konus-Wind around 2026-07-21 01:17 UT.
Wavelength coverage
- Gamma-ray: NuSTAR CsI anti-coincidence shields detected about 10 s of prompt emission, and Konus-Wind detected a longer single-pulse burst in the 75-1200 keV band with emission up to about 2 MeV.
- Hard X-ray/gamma-ray detector note: NuSTAR reports no evidence for signal above 100 keV in the CZT detectors.
No observations are mentioned in optical, infrared, ultraviolet, X-ray afterglow imaging/spectroscopy, radio, gravitational waves, or neutrinos.
Lightcurve and spectrum
- NuSTAR SINGS triggered at 2026-07-21 01:17:08 UTC; offline analysis places a rough non-barycenter-corrected T0 at 2026-07-21T01:17:02, with the burst first appearing 6 to 7 s before the trigger.
- NuSTAR CsI shield data show a burst lasting about 10 s, with peak count rate about 2000 cps over a baseline of about 1000 cps.
- Konus-Wind triggered at T0=04620.710 s UT, or 01:17:00.710.
- Konus-Wind reports a single pulse starting at about T0-0.6 s with total duration about 33 s in 75-1200 keV.
- Konus-Wind reports total fluence 2.03(-0.14,+0.18)x10^-5 erg/cm2 and 64-ms peak flux 2.41(-0.44,+0.45)x10^-6 erg/cm2/s in 20 keV - 10 MeV.
- The time-averaged Konus-Wind spectrum from T0 to T0+33.024 s is best fit by a Band model with alpha=-0.48(-0.11,+0.14), beta=-2.69(-0.22,+0.19), Ep=161(-11,+10) keV, chi2=93/97 dof.
- The Konus-Wind spectrum near maximum count rate from T0+0.256 to T0+8.448 s is best fit by a Band model with alpha=0.02(-0.15,+0.17), beta=-2.76(-0.27,+0.18), Ep=196(-12,+13) keV, chi2=84/82 dof.
Redshift
What’s special vs typical