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GCN Circular 8107

Subject
GLAST Burst Monitor detection of GRB080816
Date
2008-08-19T12:09:51Z (16 years ago)
From
Andreas von Kienlin at MPE <azk@mpe.mpg.de>
Andreas von Kienlin, Sheila McBreen and Elisabetta Bissaldi (MPE) 
report on behalf of the GLAST Burst Monitor Team: 

"At 12:04:18 UT on 2008 Aug 16, the GLAST Burst Monitor (GBM) 
triggered and located GRB 080816 (GBM 080816.503 / trigger 240581059). 
The on-ground calculated location, using the GBM trigger data, is 
RA = 156.9, Dec = +54.60 (J2000 degrees) 
(equivalent to J2000 10h 28m, +54d 36'), 
with an uncertainty of 2.3 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 Large Area Telescope (LAT) 
boresight is 55 degrees at ~T+35 sec. 

This GRB has a duration of approximately 70 s and contains 4 peaks. 
The preliminary averaged time spectrum in the 10 keV to 500 keV energy band
from T-1 to T+69 s is well fit by a power law function with an exponential 
high energy cutoff. The power law index is -0.57 +/-0.14 and the cutoff 
energy, parameterized as Epeak, is 146.7 +/-14.5 keV, with a reduced 
chi-square of 1.2 for 291 degrees of freedom. 

The fluence in the 50-300 keV band is (1.86 +/- 0.20) x 10^-5 erg/cm2. 
The 1-sec photon flux measured from T+35 sec in the 50-300 keV band 
is  3.48 +/-0.66  ph/cm2/sec. All the quoted errors are at the 90% 
confidence level.
These spectral analysis results presented above are preliminary; the final 
results will be published in the GBM GRB Catalog."
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