TITLE:   GCN CIRCULAR
NUMBER:  40150
SUBJECT: GRB 250416B: Fermi GBM Final Real-time Localization
DATE:    25/04/16 15:57:09 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 15:46:42 UT on 16 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250416B (trigger 766511207.410564 / 250416657).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 103.8, Dec = -62.2 (J2000 degrees, equivalent to J2000 06h 55m, -62d 12'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 166.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416657/quicklook/glg_skymap_all_bn250416657.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/bn250416657/quicklook/glg_healpix_all_bn250416657.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250416657/quicklook/glg_lc_medres34_bn250416657.gif