TITLE:   GCN CIRCULAR
NUMBER:  45453
SUBJECT: GRB 260827A: Fermi GBM Final Real-time Localization
DATE:    26/08/27 10:54:27 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 10:42:59 UT on 27 Aug 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260827A (trigger 809520184.770226 / 260827447).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 247.9, Dec = -53.5 (J2000 degrees, equivalent to J2000 16h 31m, -53d 30'), with a statistical uncertainty of 2.4 degrees.

The angle from the Fermi LAT boresight is 41.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260827447/quicklook/glg_skymap_all_bn260827447.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/bn260827447/quicklook/glg_healpix_all_bn260827447.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260827447/quicklook/glg_lc_medres34_bn260827447.gif