TITLE: GCN CIRCULAR NUMBER: 40814 SUBJECT: GRB 250623A: Fermi GBM Final Real-time Localization DATE: 25/06/23 16:21:45 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 16:11:12 UT on 23 Jun 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250623A (trigger 772387877.080294 / 250623674).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 233.4, Dec = -6.0 (J2000 degrees, equivalent to J2000 15h 33m, -6d 00'), with a statistical uncertainty of 10.2 degrees.

The angle from the Fermi LAT boresight is 68.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250623674/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/bn250623674/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250623674/q...

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