TITLE:   GCN CIRCULAR
NUMBER:  41846
SUBJECT: GRB 250917B: Fermi GBM Final Real-time Localization
DATE:    25/09/17 06:38:07 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 06:27:44 UT on 17 Sep 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250917B (trigger 779783269.329994 / 250917269).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 275.0, Dec = 29.0 (J2000 degrees, equivalent to J2000 18h 19m, 29d 00'), with a statistical uncertainty of 6.2 degrees.

The angle from the Fermi LAT boresight is 25.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250917269/quicklook/glg_skymap_all_bn250917269.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/bn250917269/quicklook/glg_healpix_all_bn250917269.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250917269/quicklook/glg_lc_medres34_bn250917269.gif