TITLE: GCN CIRCULAR NUMBER: 40529 SUBJECT: GRB 250522A: Fermi GBM Final Real-time Localization DATE: 25/05/22 22:12:30 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 22:01:59 UT on 22 May 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250522A (trigger 769644124.77991 / 250522918).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 37.3, Dec = -5.4 (J2000 degrees, equivalent to J2000 02h 29m, -5d 24'), with a statistical uncertainty of 16.9 degrees.

The angle from the Fermi LAT boresight is 60.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250522918/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/bn250522918/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250522918/q...

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