TITLE: GCN CIRCULAR NUMBER: 39547 SUBJECT: GRB 250228A: Fermi GBM Final Localization DATE: 25/03/02 09:43:31 GMT FROM: Marianna Dafčíková at Masaryk University 500025@mail.muni.cz

The Fermi GBM team reports the detection of a likely SHORT GRB

"At 07:23:46.16 UT on 28 February 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250228A (trigger 762420231/250228308).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 94.90, Dec = -46.81 (J2000 degrees, equivalent to J2000 6h 19m, -46d 48'), with a statistical uncertainty of 11.91 degrees.

The angle from the Fermi LAT boresight is 27 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250228308/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/bn250228308/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250228308/q..."

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