[vsnet-grb-info 6741] GRB081006: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8341
SUBJECT: GRB081006: Fermi GBM detection
DATE:    08/10/08 19:09:04 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <avdhorst at science.uva.nl>

A.J. van der Horst (NASA/ORAU) reports on behalf of the Fermi GBM Team:

"At 14:29:34 UT on 6 October 2008, the Fermi GBM triggered and located
GRB 081006 (trigger 244996175 / 081006.604).
The on-ground calculated location, using the GBM trigger data, is
RA = 142.4, Dec = -67.4 (J2000 degrees, equivalent to 9h 30m, -67d 24'),
with an uncertainty of 4.5 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 16 degrees.

This GRB is ~7 seconds long. The time-averaged spectrum (8 keV-30 MeV)
from T0-3.8 to T0+3.3 s is best fit by a Band function with
alpha = -0.77 +/- 0.24, beta = -1.80 +/- 0.22 and Epeak = 1135 +/- 826 keV.
The value of Epeak is not well constrained, but the Band function
provides a significantly better fit than a single power law or a power
law with exponential cutoff. The fluence (50-300 keV) is 7.1E-7 erg/cm^2.

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