TITLE:   GCN CIRCULAR
NUMBER:  37886
SUBJECT: GRB 241025A: Fermi GBM Observation
DATE:    24/10/25 21:10:23 GMT
FROM:    Matt Godwin <msg0028@uah.edu>

Matt Godwin (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team:

"At 01:36:26.89 UT on 25 October 2024, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 241025A (trigger 751512991/241025067).
which was also detected by Swift BAT (V. D'Elia et al. 2024, GCN 37859) and Einstein Probe (D.Y. Li et al. 2024, GCN 37864)
The Fermi GBM on-ground location is consistent with the Swift BAT position.

The angle from the Fermi LAT boresight is 47 degrees.

The GBM light curve consists of multiple close peaks with a duration (T90)
of about 124 s (50-300 keV). The time-averaged spectrum
from T0+2.3 to T0+125.2 s is best fit by a Band function.
The power law index is -0.93 +/- 0.06 and the cutoff energy,
parameterized as Epeak, is 235 +/- 22 keV.

The event fluence (10-1000 keV) in this time interval is
(1.46 +/- 0.06)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+46 s in the 10-1000 keV band is 3 +/- 0.2 ph/s/cm^2.

A power law function with an exponential high-energy cutoff fits the spectrum equally well.
The power law index is -0.92 +/- 0.05 and the cutoff energy, parameterized as
Epeak, is 232 +/- 18 keV.

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/"