TITLE:   GCN CIRCULAR
NUMBER:  41874
SUBJECT: GRB 250919A: Fermi GBM Final Real-time Localization
DATE:    25/09/19 00:39:24 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 00:28:52 UT on 19 Sep 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250919A (trigger 779934537.284108 / 250919020).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 303.5, Dec = -49.8 (J2000 degrees, equivalent to J2000 20h 14m, -49d 47'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 57.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250919020/quicklook/glg_skymap_all_bn250919020.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/bn250919020/quicklook/glg_healpix_all_bn250919020.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250919020/quicklook/glg_lc_medres34_bn250919020.gif