TITLE:   GCN CIRCULAR
NUMBER:  42747
SUBJECT: GRB 251118B: Fermi GBM Final Real-time Localization
DATE:    25/11/18 22:50:34 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 22:40:05 UT on 18 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251118B (trigger 785198410.034588 / 251118945).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 242.6, Dec = 26.9 (J2000 degrees, equivalent to J2000 16h 10m, 26d 53'), with a statistical uncertainty of 10.0 degrees.

The angle from the Fermi LAT boresight is 81.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/quicklook/glg_skymap_all_bn251118945.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/quicklook/glg_healpix_all_bn251118945.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251118945/quicklook/glg_lc_medres34_bn251118945.gif