TITLE: GCN CIRCULAR NUMBER: 40763 SUBJECT: GRB 250617B: Fermi GBM Final Localization DATE: 25/06/18 00:14:26 GMT FROM: sumanbala2210@gmail.com

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

"At 21:01:28.19 UT on 17 June 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250617B (trigger 771886893/250617876). It is also detected by Swift-BAT/XRT (Page et al. 2025, GCN 40760)

The Fermi GBM on-ground location is consistent with the Swift-XRT position.

The angle from the Fermi LAT boresight is 91 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250617876/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/bn250617876/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250617876/q..."

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