TITLE:   GCN CIRCULAR
NUMBER:  40466
SUBJECT: GRB 250516A: Fermi GBM Final Real-time Localization
DATE:    25/05/16 14:46:00 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 14:35:29 UT on 16 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250516A (trigger 769098934.27533 / 250516608).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 333.2, Dec = 0.1 (J2000 degrees, equivalent to J2000 22h 12m, 0d 06'), with a statistical uncertainty of 8.5 degrees.

The angle from the Fermi LAT boresight is 27.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250516608/quicklook/glg_skymap_all_bn250516608.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/bn250516608/quicklook/glg_healpix_all_bn250516608.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250516608/quicklook/glg_lc_medres34_bn250516608.gif