TITLE:   GCN CIRCULAR
NUMBER:  42175
SUBJECT: GRB 251006A: Fermi GBM Observation
DATE:    25/10/09 15:08:56 GMT
FROM:    Eva MP <eva.palafox@gmail.com>

E. Palafox (INAOE), M. Godwin (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 13:27:35.03 UT on 06 October 2025, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 251006A (trigger 781450060/251006561),
which was also detected by Swift/BAT-GUANO (J. DeLaunay et al. 2025, GCN 42144)
and Glowbug (C. C. Cheung et al. 2025, GCN 42130).
The Fermi GBM on-ground location is consistent with the Swift/BAT-GUANO position.

The angle from the Fermi LAT boresight is 30 degrees.

The GBM light curve consists of one short emission with total duration (T90)
of about 1.4 s (50-300 keV). The time-averaged spectrum
from T0-0.3 to T0+0.3 s is best fit by
a Comptonized function with Epeak of 490 +/- 170 and alpha of -0.9 +/- 0.2. 

The event fluence (10-1000 keV) in this time interval is
(4.8 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.0 s in the 10-1000 keV band is 7 +/- 1 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/"