GCN Circular 44193
Subject
GRB 260402B: Fermi GBM Final Real-time Localization
Event
Date
2026-04-02T23:07:38Z (3 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 22:57:17 UT on 2 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260402B (trigger 796863442.54282 / 260402956).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 238.4, Dec = 0.2 (J2000 degrees, equivalent to J2000 15h 53m, 0d 12'), with a statistical uncertainty of 11.4 degrees.
The angle from the Fermi LAT boresight is 72.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260402956/quicklook/glg_skymap_all_bn260402956.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260402956/quicklook/glg_healpix_all_bn260402956.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260402956/quicklook/glg_lc_medres34_bn260402956.gif