TITLE:   GCN CIRCULAR
NUMBER:  41778
SUBJECT: GRB 250910B: Fermi GBM Final Real-time Localization
DATE:    25/09/10 19:02:42 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 18:52:05 UT on 10 Sep 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250910B (trigger 779223130.045678 / 250910786).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 80.2, Dec = -46.4 (J2000 degrees, equivalent to J2000 05h 20m, -46d 23'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 35.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250910786/quicklook/glg_skymap_all_bn250910786.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/bn250910786/quicklook/glg_healpix_all_bn250910786.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250910786/quicklook/glg_lc_medres34_bn250910786.gif