TITLE:   GCN CIRCULAR
NUMBER:  42790
SUBJECT: GRB 251121A: Fermi GBM Final Real-time Localization
DATE:    25/11/21 16:41:36 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 SHORT GRB

At 16:30:58 UT on 21 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251121A (trigger 785435463.990588 / 251121688).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 250.6, Dec = -19.8 (J2000 degrees, equivalent to J2000 16h 42m, -19d 48'), with a statistical uncertainty of 19.5 degrees.

The angle from the Fermi LAT boresight is 100.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251121688/quicklook/glg_skymap_all_bn251121688.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/bn251121688/quicklook/glg_healpix_all_bn251121688.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251121688/quicklook/glg_lc_medres34_bn251121688.gif