TITLE:   GCN CIRCULAR
NUMBER:  44031
SUBJECT: GRB 260316B: Fermi GBM Final Real-time Localization
DATE:    26/03/16 17:23:26 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 17:12:52 UT on 16 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260316B (trigger 795373977.681026 / 260316717).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 305.5, Dec = -79.3 (J2000 degrees, equivalent to J2000 20h 22m, -79d 17'), with a statistical uncertainty of 3.2 degrees.

The angle from the Fermi LAT boresight is 81.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260316717/quicklook/glg_skymap_all_bn260316717.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/bn260316717/quicklook/glg_healpix_all_bn260316717.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260316717/quicklook/glg_lc_medres34_bn260316717.gif