GCN 45222: GRB 260727B: Fermi GBM Final Real-time Localization

2026-07-27T03:28:02.092Z | rev 0 | event: GRB 260727B

The Fermi GBM team reports the detection of a likely LONG GRB

At 03:17:30 UT on 27 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260727B (trigger 806815055.083858 / 260727137).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 191.4, Dec = -24.5 (J2000 degrees, equivalent to J2000 12h 45m, -24d 30'), with a statistical uncertainty of 10.6 degrees.

The angle from the Fermi LAT boresight is 80.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260727137/quicklook/glg_skymap_all_bn260727137.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/bn260727137/quicklook/glg_healpix_all_bn260727137.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260727137/quicklook/glg_lc_medres34_bn260727137.gif