TITLE:   GCN CIRCULAR
NUMBER:  44676
SUBJECT: GRB 260520B: Fermi GBM Final Localization
DATE:    26/05/20 18:00:48 GMT
FROM:    Cuán de Barra at UCD <cuan.debarra@ucdconnect.ie>

The Fermi GBM team reports the detection of a likely LONG GRB

"At 09:35:52.73 UT on 20 May 2026, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB260520B (trigger 800962557/260520400).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 346.68, Dec = 39.68 (J2000 degrees, equivalent to J2000 23h 6m, -39d 40'),
with a statistical uncertainty of 14 degrees.

The angle from the Fermi LAT boresight is 21 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260520400/quicklook/glg_skymap_all_bn260520400.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/bn260520400/quicklook/glg_healpix_all_bn260520400.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260520400/quicklook/glg_lc_medres34_bn260520400.gif"