TITLE:   GCN CIRCULAR
NUMBER:  43656
SUBJECT: GRB 260209A: Fermi GBM Final Real-time Localization
DATE:    26/02/09 02:56:37 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 02:45:57 UT on 9 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260209A (trigger 792297962.23625 / 260209115).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 75.8, Dec = 33.0 (J2000 degrees, equivalent to J2000 05h 03m, 33d 00'), with a statistical uncertainty of 9.2 degrees.

The angle from the Fermi LAT boresight is 87.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260209115/quicklook/glg_skymap_all_bn260209115.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/bn260209115/quicklook/glg_healpix_all_bn260209115.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260209115/quicklook/glg_lc_medres34_bn260209115.gif