TITLE:   GCN CIRCULAR
NUMBER:  45658
SUBJECT: GRB 260920A: Fermi GBM Final Real-time Localization
DATE:    26/09/20 10:42:45 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 10:32:24 UT on 20 Sep 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260920A (trigger 811593149.787088 / 260920439).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 293.0, Dec = -31.8 (J2000 degrees, equivalent to J2000 19h 32m, -31d 48'), with a statistical uncertainty of 1.1 degrees.

The angle from the Fermi LAT boresight is 121.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260920439/quicklook/glg_skymap_all_bn260920439.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/bn260920439/quicklook/glg_healpix_all_bn260920439.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260920439/quicklook/glg_lc_medres34_bn260920439.gif