TITLE:   GCN CIRCULAR
NUMBER:  44335
SUBJECT: GRB 260418A: Fermi GBM Final Real-time Localization
DATE:    26/04/18 05:00:17 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 04:49:35 UT on 18 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260418A (trigger 798180580.203356 / 260418201).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 140.6, Dec = 29.3 (J2000 degrees, equivalent to J2000 09h 22m, 29d 18'), with a statistical uncertainty of 18.1 degrees.

The angle from the Fermi LAT boresight is 60.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260418201/quicklook/glg_skymap_all_bn260418201.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/bn260418201/quicklook/glg_healpix_all_bn260418201.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260418201/quicklook/glg_lc_medres34_bn260418201.gif