TITLE:   GCN CIRCULAR
NUMBER:  44097
SUBJECT: GRB 260323A: Fermi GBM Final Real-time Localization
DATE:    26/03/24 00:02:09 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 23:51:27 UT on 23 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260323A (trigger 796002692.989066 / 260323994).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 100.1, Dec = -77.1 (J2000 degrees, equivalent to J2000 06h 40m, -77d 05'), with a statistical uncertainty of 5.5 degrees.

The angle from the Fermi LAT boresight is 149.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260323994/quicklook/glg_skymap_all_bn260323994.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/bn260323994/quicklook/glg_healpix_all_bn260323994.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260323994/quicklook/glg_lc_medres34_bn260323994.gif