TITLE:   GCN CIRCULAR
NUMBER:  44707
SUBJECT: GRB 260526A: Fermi GBM Final Real-time Localization
DATE:    26/05/26 23:14:33 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 23:04:00 UT on 26 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260526A (trigger 801529445.20122 / 260526961).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 40.1, Dec = 43.9 (J2000 degrees, equivalent to J2000 02h 40m, 43d 53'), with a statistical uncertainty of 3.8 degrees.

The angle from the Fermi LAT boresight is 30.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260526961/quicklook/glg_skymap_all_bn260526961.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/bn260526961/quicklook/glg_healpix_all_bn260526961.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260526961/quicklook/glg_lc_medres34_bn260526961.gif