GCN Circular 8640
Subject
GRB 081206: Fermi GBM detection
Date
2008-12-08T16:10:09Z (16 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
A. von Kienlin (MPE)
reports on behalf of the Fermi GBM Team:
"At 06:35:53.02 UT on 06 December 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081206 (trigger 250238154 / 081206275).
The on-ground calculated location, using the GBM trigger
data, is RA = 120.1, DEC = 32.7 (J2000 degrees,
equivalent to 08h 00m, 32d 42'), with an uncertainty
of 5.2 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 102 degrees.
The GBM light curve consists of a single peak
with a duration (T90) of about 24 s (8-1000 keV).
The time-averaged spectrum from T0-6.144 s to T0+15.360 s is
well fit by a power law function with an exponential
high energy cutoff. The power law index is -0.11 +/- 0.24 and
the cutoff energy, parameterized as Epeak, is 180 +/- 23 keV
(chi squared 245 for 236 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(4.0 +/- 0.6)E-06 erg/cm^2. The 1-sec photon flux measured
starting from T0+3.072 s in the 8-1000 keV band
is 2.4 +/- 0.3 ph/s/cm^2.
A Band function fits the spectrum equally well
(chi squared 242 for 235 d.o.f.) with Epeak= 151 +/- 29 keV,
alpha = 0.13 +/- 0.37 and beta = -2.2 +/- 0.4.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."