TITLE: GCN CIRCULAR NUMBER: 40104 SUBJECT: GRB 250407A: Fermi GBM Final Real-time Localization DATE: 25/04/07 15:58:59 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 15:48:21 UT on 7 Apr 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250407A (trigger 765733706.065626 / 250407659).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 110.3, Dec = 42.0 (J2000 degrees, equivalent to J2000 07h 21m, 42d 00'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 118.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250407659/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/bn250407659/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250407659/q...

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