TITLE:   GCN CIRCULAR
NUMBER:  40515
SUBJECT: GRB 250521C: Fermi GBM Final Localization
DATE:    25/05/21 18:36:09 GMT
FROM:    Lorenzo Scotton at UAH <lscottongcn@outlook.com>

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

"At 13:31:01.20 UT on 21 May 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250521C (trigger 769527066/250521563).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 105.00, Dec = 65.63 (J2000 degrees, equivalent to J2000 7h 0m, +65d 37'),
with a statistical uncertainty of 16.05 degrees.

The angle from the Fermi LAT boresight is 91 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250521563/quicklook/glg_skymap_all_bn250521563.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250521563/quicklook/glg_healpix_all_bn250521563.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250521563/quicklook/glg_lc_medres34_bn250521563.gif"