TITLE: GCN CIRCULAR NUMBER: 40342 SUBJECT: GRB 250504A: Fermi GBM Final Real-time Localization DATE: 25/05/04 23:36:31 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 23:25:54 UT on 4 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250504A (trigger 768093959.78286 / 250504976).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 265.4, Dec = -40.9 (J2000 degrees, equivalent to J2000 17h 41m, -40d 53'), with a statistical uncertainty of 2.1 degrees.
The angle from the Fermi LAT boresight is 113.0 degrees.
The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250504976/q...
The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250504976/q...
The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250504976/q...
View this GCN Circular online at https://gcn.nasa.gov/circulars/40342. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...