TITLE: GCN CIRCULAR NUMBER: 39479 SUBJECT: GRB 250226A: Fermi GBM Final Real-time Localization DATE: 25/02/26 06:42:51 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 06:34:57 UT on 26 Feb 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250226A (trigger 762244502.334384 / 250226274).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 222.1, Dec = 23.8 (J2000 degrees, equivalent to J2000 14h 48m, 23d 48'), with a statistical uncertainty of 3.9 degrees.

The angle from the Fermi LAT boresight is 111.0 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250226274/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/bn250226274/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250226274/q...

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