GCN Circular 44631
Subject
GRB 260516A: Fermi GBM Final Real-time Localization
Event
Date
2026-05-16T03:01:20Z (14 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 02:50:48 UT on 16 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260516A (trigger 800592653.936132 / 260516119).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 111.5, Dec = -37.6 (J2000 degrees, equivalent to J2000 07h 26m, -37d 36'), with a statistical uncertainty of 7.7 degrees.
The angle from the Fermi LAT boresight is 163.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260516119/quicklook/glg_skymap_all_bn260516119.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/bn260516119/quicklook/glg_healpix_all_bn260516119.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260516119/quicklook/glg_lc_medres34_bn260516119.gif