TITLE: GCN CIRCULAR NUMBER: 42034 SUBJECT: GRB 251001A: Fermi GBM Final Real-time Localization DATE: 25/10/01 02:51:32 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 02:40:56 UT on 1 Oct 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251001A (trigger 780979261.951484 / 251001112).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 224.4, Dec = -56.2 (J2000 degrees, equivalent to J2000 14h 57m, -56d 12'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 116.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251001112/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/bn251001112/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251001112/q...

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