GCN Circular 43969
Subject
GRB 260312B: Fermi GBM Final Real-time Localization
Event
Date
2026-03-12T09:57:18Z (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 09:46:46 UT on 12 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260312B (trigger 795001611.054834 / 260312407).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 25.9, Dec = -3.9 (J2000 degrees, equivalent to J2000 01h 43m, -3d 53'), with a statistical uncertainty of 1.9 degrees.
The angle from the Fermi LAT boresight is 67.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260312407/quicklook/glg_skymap_all_bn260312407.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/bn260312407/quicklook/glg_healpix_all_bn260312407.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260312407/quicklook/glg_lc_medres34_bn260312407.gif