TITLE:   GCN CIRCULAR
NUMBER:  44508
SUBJECT: GRB 260510A: Fermi GBM Final Real-time Localization
DATE:    26/05/10 02:57:06 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 02:46:19 UT on 10 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260510A (trigger 800073984.34868 / 260510115).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 0.5, Dec = -41.9 (J2000 degrees, equivalent to J2000 00h 02m, -41d 53'), with a statistical uncertainty of 6.1 degrees.

The angle from the Fermi LAT boresight is 84.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260510115/quicklook/glg_skymap_all_bn260510115.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/bn260510115/quicklook/glg_healpix_all_bn260510115.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260510115/quicklook/glg_lc_medres34_bn260510115.gif