TITLE:   GCN CIRCULAR
NUMBER:  39352
SUBJECT: GRB 250217B: Fermi GBM Final Real-time Localization
DATE:    25/02/17 11:35:46 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 11:27:19 UT on 17 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250217B (trigger 761484444.589826 / 250217477).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 231.3, Dec = 34.9 (J2000 degrees, equivalent to J2000 15h 25m, 34d 53'), with a statistical uncertainty of 6.0 degrees.

The angle from the Fermi LAT boresight is 121.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250217477/quicklook/glg_skymap_all_bn250217477.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/bn250217477/quicklook/glg_healpix_all_bn250217477.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250217477/quicklook/glg_lc_medres34_bn250217477.gif