[vsnet-grb-info 6508] GRB080818B: GLAST Burst Monitor detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8116
SUBJECT: GRB080818B: GLAST Burst Monitor detection
DATE:    08/08/22 20:45:13 GMT
FROM:    Colleen A. Wilson at NASA/MSFC/NSSTC  <colleen.wilson at nasa.gov>

C.A. Wilson-Hodge (NASA/MSFC), A.J. van der Horst (NASA/ORAU), report on
behalf of the GLAST Burst Monitor Team:

"At 22:40:49 UT on 18 August 2008, the GLAST Burst Monitor (GBM)
triggered and located GRB 080818B (trigger 240792050 / 080818.945).
The on-ground calculated location, using the GBM trigger data, is
RA = 98.1, Dec = +7.4 (J2000 degrees)(equivalent to J2000 06h 32m, +7d 60')
with an uncertainty of 7.7 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 68 degrees.

This GRB was about 10 s long with one peak.  The time-averaged spectrum
(8-950 keV) from T-1.3 to T+10.0 s is best fit with a Comptonized spectrum
(power law times exponential cutoff).   The power law index is -1.3 +/- 0.1
and the cutoff energy, parameterized as Epeak, is 80 +/- 11 keV. The
fluence from 50-300 keV is 1E-6 erg/cm^2.
 
The spectral analysis results presented above are preliminary; the final
results will be published in the GBM GRB Catalog.