TITLE:   GCN CIRCULAR
NUMBER:  43833
SUBJECT: GRB 260225B: Fermi GBM Final Real-time Localization
DATE:    26/02/25 15:24:47 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 15:14:07 UT on 25 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260225B (trigger 793725252.479854 / 260225635).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 326.4, Dec = 0.9 (J2000 degrees, equivalent to J2000 21h 45m, 0d 54'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 66.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260225635/quicklook/glg_skymap_all_bn260225635.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/bn260225635/quicklook/glg_healpix_all_bn260225635.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260225635/quicklook/glg_lc_medres34_bn260225635.gif