GCN Circular 43028
Subject
GRB 251208B: Fermi GBM Final Real-time Localization
Event
Date
2025-12-08T10:27:53Z (2 days ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 10:17:17 UT on 8 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251208B (trigger 786881842.294214 / 251208429).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 212.3, Dec = 30.1 (J2000 degrees, equivalent to J2000 14h 09m, 30d 06'), with a statistical uncertainty of 5.8 degrees.
The angle from the Fermi LAT boresight is 25.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251208429/quicklook/glg_skymap_all_bn251208429.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/bn251208429/quicklook/glg_healpix_all_bn251208429.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251208429/quicklook/glg_lc_medres34_bn251208429.gif