GCN Circular 8483
Subject
GRB 081025: Fermi GBM observation
Date
2008-11-05T17:11:18Z (16 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE) and E. Bissaldi (MPE)
report on behalf of the Fermi GBM Team:
"At 08:23:05.29 UT on 25 October 2008, the Fermi GBM triggered and located
GRB 081025 (trigger 246615786 / 081025349) which was also detected by the
SWIFT-BAT Slew Survey (A. Copete et al. 2008, GCN 8409) and followed up by
SWIFT-XRT (J. Mao et al. 2008, GCN 8411). The GBM on-ground location is
consistent with the Swift position.
The GBM light curve shows a multipeaked structure with a duration (T90) of
about 45 s (8-1000 keV). The time-averaged spectrum from T0-1.536 s to
T0+24.064 s is best fit by an exponentially cutoff power law model with
Epeak = 251 +/- 25 keV, and index -0.35 +/- 0.13 (chi squared 736 for 700
d.o.f.). The event fluence (8-1000 keV) in this time interval is
(7.1 +/- 0.5)E-06 erg/cm^2. The 1-sec photon flux measured from T+2.56 sec
in the 8-1000 keV band is 4.50 +/- 0.22 ph/cm2/sec. A Band function fit
the spectrum equally well (chi squared 732 for 699 d.o.f.) with
Epeak= 200 +/- 33 keV, alpha = 0.15 +/- 0.22 and beta = -2.05 +/- 0.25.
The spectral analysis results presented above are preliminary; final results
will be published in the GBM GRB Catalog."