TITLE: GCN CIRCULAR NUMBER: 39430 SUBJECT: GRB 250223A: Fermi GBM Final Real-time Localization DATE: 25/02/23 16:46:39 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 16:36:11 UT on 23 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250223A (trigger 762021376.807148 / 250223692).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 340.6, Dec = -40.3 (J2000 degrees, equivalent to J2000 22h 42m, -40d 17'), with a statistical uncertainty of 31.6 degrees.

The angle from the Fermi LAT boresight is 95.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250223692/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/bn250223692/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250223692/q...

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