GCN Circular 41111

Jacob Smith (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 13:44:22.95 UT on 17 July 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 250717B (trigger 774452667/250717572).
which was also detected by Swift/BAT-GUANO (Samuele Ronchini et al. 2025, GCN 41110
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 ).
The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.

The angle from the Fermi LAT boresight is 74 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 6.4 s (50-300 keV). The time-averaged spectrum
from T0+0.002 to T0+7.360 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.9 +/- 0.1 and the cutoff energy,
parameterized as Epeak, is 75 +/- 5 keV.
A Band function fits equally well with Epeak = 72 +/- 6 keV, alpha = -0.9 +/- 0.2 and beta = -3.2 +/- 0.9.

The event fluence (10-1000 keV) in this time interval is
(1.36 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.13 s in the 10-1000 keV band is 6.1 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"