TITLE: GCN CIRCULAR NUMBER: 41343 SUBJECT: GRB 250813A: Fermi GBM Final Localization DATE: 25/08/13 13:54:08 GMT FROM: eliza.neights@gmail.com

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

"At 01:46:03.86 UT on 13 August 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250813A (trigger 776742368/250813074).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 355.90, Dec = 57.28 (J2000 degrees, equivalent to J2000 23h 43m, +57d 16'), with a statistical uncertainty of 3.06 degrees.

The angle from the Fermi LAT boresight is 19 degrees.

The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250813074/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/bn250813074/q...

The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250813074/q..."

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