TITLE:   GCN CIRCULAR
NUMBER:  44331
SUBJECT: GRB 260417B: Fermi GBM Final Real-time Localization
DATE:    26/04/17 15:54:29 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 15:43:55 UT on 17 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260417B (trigger 798133440.23068 / 260417655).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 264.8, Dec = -27.4 (J2000 degrees, equivalent to J2000 17h 39m, -27d 23'), with a statistical uncertainty of 8.4 degrees.

The angle from the Fermi LAT boresight is 29.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260417655/quicklook/glg_skymap_all_bn260417655.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260417655/quicklook/glg_healpix_all_bn260417655.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260417655/quicklook/glg_lc_medres34_bn260417655.gif