General information
GRB 260723A was reported by Fermi GBM as a likely long GRB detected at 2026-07-23 13:54:48.40 UT, with an on-ground localization at RA 284.5 deg and Dec 7.7 deg. The provided follow-up circulars discuss EP260723a, including an EP/WXT transient at 2026-07-23T18:56:01 UTC, SVOM/VT optical detections, and SVOM/ECLAIRs upper limits.
Wavelength coverage
- Gamma-ray: Fermi GBM detected and localized a likely long GRB; the angle from the Fermi LAT boresight was 87 deg.
- X-ray: EP/WXT is reported to have detected EP260723a with a duration of about 100 s.
- Hard X-ray/soft gamma-ray: SVOM/ECLAIRs searched the EP260723a interval and found no statistically significant signal, deriving 3-sigma 4-120 keV flux upper limits.
- Optical: SVOM/VT detected the optical counterpart in both VT_B and VT_R bands at about 11 hours after trigger.
Bands with no observations mentioned: radio, millimeter/submillimeter, infrared, ultraviolet, neutrino, gravitational wave.
Lightcurve and spectrum
- Fermi GBM classified GRB 260723A as a likely long GRB.
- EP/WXT is quoted as detecting EP260723a with a duration of about 100 s.
- SVOM/VT measured VT_B = 22.1 +/- 0.1 AB at 10.98 h and VT_R = 21.9 +/- 0.2 AB at 10.96 h; the photometry was not corrected for Galactic extinction.
- SVOM/ECLAIRs found no significant signal from T0 - 500 s to T0 + 3000 s.
- For T0 to T0 + 100 s, ECLAIRs derived a 3-sigma upper limit of 2.4e-9 erg/cm^2/s in 4-120 keV assuming a power-law photon index of 1.4, or 1.5e-9 erg/cm^2/s assuming a soft Band spectrum with Epeak = 25 keV, alpha = -1.5, and beta = -3.0.
Redshift
What’s special vs typical