TITLE:   GCN CIRCULAR
NUMBER:  43614
SUBJECT: GRB 260204B: Fermi GBM Final Real-time Localization
DATE:    26/02/04 17:00:30 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 16:50:06 UT on 4 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260204B (trigger 791916611.958652 / 260204701).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 338.5, Dec = -50.1 (J2000 degrees, equivalent to J2000 22h 33m, -50d 06'), with a statistical uncertainty of 6.4 degrees.

The angle from the Fermi LAT boresight is 70.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260204701/quicklook/glg_skymap_all_bn260204701.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/bn260204701/quicklook/glg_healpix_all_bn260204701.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260204701/quicklook/glg_lc_medres34_bn260204701.gif