GCN Circular 43955
Subject
GRB 260310B: Fermi GBM Final Real-time Localization
Event
Date
2026-03-10T21:49:02Z (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 21:41:23 UT on 10 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260310B (trigger 794871688.893658 / 260310904).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 119.6, Dec = 12.9 (J2000 degrees, equivalent to J2000 07h 58m, 12d 54'), with a statistical uncertainty of 6.7 degrees.
The angle from the Fermi LAT boresight is 68.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260310904/quicklook/glg_skymap_all_bn260310904.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/bn260310904/quicklook/glg_healpix_all_bn260310904.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260310904/quicklook/glg_lc_medres34_bn260310904.gif