TITLE:   GCN CIRCULAR
NUMBER:  42131
SUBJECT: GRB 251006B: Fermi GBM Final Real-time Localization
DATE:    25/10/06 20:15:37 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 20:05:04 UT on 6 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251006B (trigger 781473909.040226 / 251006837).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 40.5, Dec = -4.0 (J2000 degrees, equivalent to J2000 02h 42m, -4d 00'), with a statistical uncertainty of 1.2 degrees.

The angle from the Fermi LAT boresight is 105.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251006837/quicklook/glg_skymap_all_bn251006837.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/bn251006837/quicklook/glg_healpix_all_bn251006837.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251006837/quicklook/glg_lc_medres34_bn251006837.gif