TITLE:   GCN CIRCULAR
NUMBER:  42502
SUBJECT: GRB 251028B: Fermi GBM Final Localization Correction
DATE:    25/10/28 10:12:02 GMT
FROM:    Christian Malacaria at INAF-OAR <cmalacaria.astro@gmail.com>

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

"At 07:48:06.71 UT on 28 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 251028B (trigger 783330491/251028325).
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 = 337.82, Dec = 45.75 (J2000 degrees, equivalent to J2000 22h 31m, +45d 45'),
with a statistical uncertainty of 3.69 degrees.

The angle from the Fermi LAT boresight is 119 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251028325/quicklook/glg_skymap_all_bn251028325.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251028325/quicklook/glg_healpix_all_bn251028325.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251028325/quicklook/glg_lc_medres34_bn251028325.gif"