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GCN Circular 8550

Subject
GRB 081118: Fermi GBM detection.
Date
2008-11-24T18:06:29Z (15 years ago)
From
Narayana Bhat at U Alabama/Huntsville/GBM <Narayana.Bhat@nasa.gov>
P. N. Bhat (UAH), R. D. Preece (UAH) and A.J. van der Horst (NASA/ORAU)
report on behalf of the Fermi GBM Team:

At 21:00:53.53 UT on 18 November 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081118B (trigger 248734854 / 081118876).

The on-ground calculated location, using the GBM trigger
data, is RA = 54.0, DEC = -50.4 (J2000 degrees,
equivalent to 03 h 36 m, 50 d 24'), with an uncertainty
of 2.9 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 41 degrees.

The GBM light curve consists of primarily 2 pulses.
It has a duration (T90) of about 20 s (8-1000 keV).
The time-averaged spectrum from T0-2.6 s to T0+27 s is
well fit by a Band function with Epeak = 41.2 +/- 3.9,
alpha = 0.8 +/- 0.5 and beta = -2.14 +/- 0.08.

The event fluence (8-1000 keV) in this time interval is
(1.12 +/- 0.61)E-7 erg/cm^2. The 1-sec peak photon flux
in the 8-1000 keV band is 0.67 +/- 0.37 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog.
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