TITLE:   GCN CIRCULAR
NUMBER:  44741
SUBJECT: GRB 260530A: Fermi GBM Final Real-time Localization
DATE:    26/05/30 06:21:32 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 06:10:52 UT on 30 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260530A (trigger 801814257.752724 / 260530258).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 93.0, Dec = 12.7 (J2000 degrees, equivalent to J2000 06h 12m, 12d 41'), with a statistical uncertainty of 6.4 degrees.

The angle from the Fermi LAT boresight is 87.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260530258/quicklook/glg_skymap_all_bn260530258.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/bn260530258/quicklook/glg_healpix_all_bn260530258.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260530258/quicklook/glg_lc_medres34_bn260530258.gif