GCN Circular 43795
Subject
GRB 260221B: Fermi GBM Final Real-time Localization
Event
Date
2026-02-21T16:33:30Z (2 days ago)
Edited On
2026-02-23T02:05:50Z (12 hours ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov>
Via
email
The Fermi GBM team reports the detection of a likely LONG GRB
At 16:22:52 UT on 21 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260221B (trigger 793383777.240036 / 260221683).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 213.3, Dec = 51.9 (J2000 degrees, equivalent to J2000 14h 13m, 51d 53'), with a statistical uncertainty of 6.6 degrees.
The angle from the Fermi LAT boresight is 128.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260221683/quicklook/glg_skymap_all_bn260221683.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/bn260221683/quicklook/glg_healpix_all_bn260221683.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260221683/quicklook/glg_lc_medres34_bn260221683.gif