GCN Circular 43069
Subject
GRB 251211A: Fermi GBM Final Real-time Localization
Event
Date
2025-12-11T02:51:35Z (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 02:40:59 UT on 11 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251211A (trigger 787113664.18548 / 251211112).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 181.9, Dec = -32.3 (J2000 degrees, equivalent to J2000 12h 07m, -32d 17'), with a statistical uncertainty of 6.4 degrees.
The angle from the Fermi LAT boresight is 28.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251211112/quicklook/glg_skymap_all_bn251211112.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/bn251211112/quicklook/glg_healpix_all_bn251211112.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251211112/quicklook/glg_lc_medres34_bn251211112.gif