TITLE:   GCN CIRCULAR
NUMBER:  44299
SUBJECT: GRB 260415A: Fermi GBM Final Real-time Localization
DATE:    26/04/15 04:54:40 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 LONG GRB

At 04:43:59 UT on 15 Apr 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260415A (trigger 797921044.314306 / 260415197).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 58.5, Dec = -24.0 (J2000 degrees, equivalent to J2000 03h 53m, -24d 00'), with a statistical uncertainty of 5.5 degrees.

The angle from the Fermi LAT boresight is 92.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260415197/quicklook/glg_skymap_all_bn260415197.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/bn260415197/quicklook/glg_healpix_all_bn260415197.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260415197/quicklook/glg_lc_medres34_bn260415197.gif