GCN Circular 41803

The Fermi GBM team reports the detection of a likely LONG GRB

"At 23:50:11.34 UT on 10 September 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250910C (trigger 779241016/250910993).
This trigger was initially classified as Unreliable location by the flight software,
but is in fact a GRB.

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 47.58, Dec = -35.77 (J2000 degrees, equivalent to J2000 3h 10m, -35d 46'),
with a statistical uncertainty of 10.95 degrees.

The angle from the Fermi LAT boresight is 46 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250910993/quicklook/glg_skymap_all_bn250910993.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/bn250910993/quicklook/glg_healpix_all_bn250910993.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250910993/quicklook/glg_lc_medres34_bn250910993.gif"