TITLE: GCN CIRCULAR NUMBER: 38976 SUBJECT: GRB 250118A: Fermi GBM Final Real-time Localization DATE: 25/01/18 18:41:33 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 SHORT GRB

At 18:31:11 UT on 18 Jan 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250118A (trigger 758917876.966464 / 250118772).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 263.8, Dec = 38.8 (J2000 degrees, equivalent to J2000 17h 35m, 38d 47'), with a statistical uncertainty of 10.7 degrees.

The angle from the Fermi LAT boresight is 14.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250118772/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/bn250118772/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250118772/q...

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