TITLE:   GCN CIRCULAR
NUMBER:  43186
SUBJECT: GRB 251222A: Fermi GBM Final Real-time Localization
DATE:    25/12/22 17:16:31 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 17:05:51 UT on 22 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251222A (trigger 788115956.26632 / 251222712).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 75.7, Dec = -5.3 (J2000 degrees, equivalent to J2000 05h 02m, -5d 17'), with a statistical uncertainty of 2.0 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/bn251222712/quicklook/glg_skymap_all_bn251222712.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/bn251222712/quicklook/glg_healpix_all_bn251222712.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251222712/quicklook/glg_lc_medres34_bn251222712.gif