TITLE:   GCN CIRCULAR
NUMBER:  40348
SUBJECT: GRB 250505A: Fermi GBM Final Real-time Localization
DATE:    25/05/05 08:19:09 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 08:08:39 UT on 5 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250505A (trigger 768125324.539978 / 250505339).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 104.6, Dec = -10.3 (J2000 degrees, equivalent to J2000 06h 58m, -10d 18'), with a statistical uncertainty of 3.4 degrees.

The angle from the Fermi LAT boresight is 22.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250505339/quicklook/glg_skymap_all_bn250505339.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/bn250505339/quicklook/glg_healpix_all_bn250505339.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250505339/quicklook/glg_lc_medres34_bn250505339.gif