TITLE:   GCN CIRCULAR
NUMBER:  46024
SUBJECT: GRB 261025A: Fermi GBM Final Localization Correction
DATE:    26/10/25 11:34:37 GMT
FROM:    A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca@unitn.it>

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

"At 06:00:01.80 UT on 25 October 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 261025A (trigger 814600806/261025250).
This trigger was initially classified as Distant Particles by the flight software,
but is in fact a GRB.

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 297.81, Dec = 67.39 (J2000 degrees, equivalent to J2000 19h 51m, +67d 23'),
with a statistical uncertainty of 5.35 degrees.

The angle from the Fermi LAT boresight is 36 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261025250/quicklook/glg_skymap_all_bn261025250.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/bn261025250/quicklook/glg_healpix_all_bn261025250.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261025250/quicklook/glg_lc_medres34_bn261025250.gif"