TITLE:   GCN CIRCULAR
NUMBER:  44493
SUBJECT: GRB 260507A: Fermi GBM Final Real-time Localization
DATE:    26/05/07 20:38:34 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 20:28:00 UT on 7 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260507A (trigger 799878485.453562 / 260507853).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 287.5, Dec = -21.3 (J2000 degrees, equivalent to J2000 19h 10m, -21d 18'), with a statistical uncertainty of 2.4 degrees.

The angle from the Fermi LAT boresight is 79.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260507853/quicklook/glg_skymap_all_bn260507853.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/bn260507853/quicklook/glg_healpix_all_bn260507853.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260507853/quicklook/glg_lc_medres34_bn260507853.gif