TITLE:   GCN CIRCULAR
NUMBER:  44523
SUBJECT: GRB 260510D: Fermi GBM Final Real-time Localization
DATE:    26/05/10 20:48:45 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 SHORT GRB

At 20:38:08 UT on 10 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260510D (trigger 800138293.771294 / 260510860).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 3.0, Dec = 37.4 (J2000 degrees, equivalent to J2000 00h 12m, 37d 23'), with a statistical uncertainty of 13.9 degrees.

The angle from the Fermi LAT boresight is 61.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260510860/quicklook/glg_skymap_all_bn260510860.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/bn260510860/quicklook/glg_healpix_all_bn260510860.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260510860/quicklook/glg_lc_medres34_bn260510860.gif