General information
GRB 260604B was detected at about 2026-06-04 08:45:55 UT by Fermi/GBM and later reported by SVOM/GRM, 239Alferov, and Konus-Wind. The Fermi/GBM localization is RA = 173.4 deg, Dec = -19.9 deg with a statistical uncertainty of 10.8 deg.
Wavelength coverage
- Gamma-ray: Fermi/GBM triggered and localized the event; SVOM/GRM detected it and reported prompt duration, spectrum, and fluence; 239Alferov detected a multi-peaked light curve; Konus-Wind also detected it in waiting mode.
- Optical/soft gamma trigger context: the burst position was outside the SVOM/ECLAIRs field of view.
No observations are mentioned in radio, infrared, optical, ultraviolet, X-ray afterglow follow-up, neutrinos, or gravitational waves.
Lightcurve and spectrum
- Fermi/GBM initially reported the event as a likely short GRB.
- SVOM/GRM reports multiple pulses with T90 = 17 +9/-5 s in the 15-5000 keV band.
- SVOM/GRM fitted the time-averaged spectrum from T0-15 to T0+25 s with a power law of index -1.67 +0.10/-0.11.
- SVOM/GRM reports fluence of (3.8 +0.8/-0.8)e-6 erg/cm^2 in 10-1000 keV over T0-15 to T0+25 s.
- 239Alferov reports a multi-peaked structure with duration of about 8 s and emission seen up to about 500 keV.
Redshift
What’s special vs typical
The event is supported by multiple independent gamma-ray detections, including Fermi/GBM, SVOM/GRM, 239Alferov, and Konus-Wind. The classification is somewhat notable because the circulars differ between an initial likely short-GRB label and later duration measurements or wording consistent with a longer event.