TITLE:   GCN CIRCULAR
NUMBER:  43987
SUBJECT: GRB 260313A: Fermi GBM Final Real-time Localization
DATE:    26/03/13 12:11:03 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 12:00:28 UT on 13 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260313A (trigger 795096033.584074 / 260313500).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 53.4, Dec = 33.3 (J2000 degrees, equivalent to J2000 03h 33m, 33d 17'), with a statistical uncertainty of 14.1 degrees.

The angle from the Fermi LAT boresight is 152.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260313500/quicklook/glg_skymap_all_bn260313500.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/bn260313500/quicklook/glg_healpix_all_bn260313500.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260313500/quicklook/glg_lc_medres34_bn260313500.gif