TITLE:   GCN CIRCULAR
NUMBER:  46114
SUBJECT: GRB 261030A: Fermi GBM Final Real-time Localization
DATE:    26/10/30 16:37:56 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 16:27:22 UT on 30 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261030A (trigger 815070447.276984 / 261030686).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 340.6, Dec = 7.1 (J2000 degrees, equivalent to J2000 22h 42m, 7d 05'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 74.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261030686/quicklook/glg_skymap_all_bn261030686.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/bn261030686/quicklook/glg_healpix_all_bn261030686.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261030686/quicklook/glg_lc_medres34_bn261030686.gif