TITLE:   GCN CIRCULAR
NUMBER:  39748
SUBJECT: GRB 250317A: Fermi GBM Final Real-time Localization
DATE:    25/03/17 00:16:07 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 LONG GRB

At 00:05:29 UT on 17 Mar 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250317A (trigger 763862734.52183 / 250317004).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 148.2, Dec = -25.4 (J2000 degrees, equivalent to J2000 09h 52m, -25d 23'), with a statistical uncertainty of 6.3 degrees.

The angle from the Fermi LAT boresight is 23.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250317004/quicklook/glg_skymap_all_bn250317004.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/bn250317004/quicklook/glg_healpix_all_bn250317004.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250317004/quicklook/glg_lc_medres34_bn250317004.gif