TITLE:   GCN CIRCULAR
NUMBER:  45377
SUBJECT: GRB 260813A: Fermi GBM Final Real-time Localization
DATE:    26/08/13 19:26:57 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 19:16:22 UT on 13 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260813A (trigger 808341387.08523 / 260813803).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 231.4, Dec = -57.8 (J2000 degrees, equivalent to J2000 15h 25m, -57d 47'), with a statistical uncertainty of 2.5 degrees.

The angle from the Fermi LAT boresight is 46.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260813803/quicklook/glg_skymap_all_bn260813803.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/bn260813803/quicklook/glg_healpix_all_bn260813803.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260813803/quicklook/glg_lc_medres34_bn260813803.gif