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GCN Circular 41228

Subject
GRB 250804A: Fermi GBM Final Localization
Date
2025-08-04T15:33:20Z (a month ago)
From
rhamburg@usra.edu
Via
Web form
The Fermi GBM team reports the detection of a likely SHORT GRB.

"At 11:38:03.48 UT on 04 August 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250804A (trigger 776000288/250804485).
This trigger was initially classified as Below Horizon by the flight software,
but is in fact a GRB.

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 114.09, Dec = 42.02 (J2000 degrees, equivalent to J2000 7h 36m, +42d 1'),
with a statistical uncertainty of 19.32 degrees.

The angle from the Fermi LAT boresight is 44 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250804485/quicklook/glg_skymap_all_bn250804485.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250804485/quicklook/glg_healpix_all_bn250804485.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250804485/quicklook/glg_lc_medres34_bn250804485.gif"

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