TITLE:   GCN CIRCULAR
NUMBER:  44891
SUBJECT: GRB 260610A: Fermi GBM Final Real-time Localization
DATE:    26/06/10 10:18:35 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 10:07:46 UT on 10 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260610b (trigger 802778871.805202 / 260610422).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 354.7, Dec = 8.4 (J2000 degrees, equivalent to J2000 23h 38m, 8d 24'), with a statistical uncertainty of 10.5 degrees.

The angle from the Fermi LAT boresight is 102.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260610422/quicklook/glg_skymap_all_bn260610422.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/bn260610422/quicklook/glg_healpix_all_bn260610422.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260610422/quicklook/glg_lc_medres34_bn260610422.gif