[vsnet-grb-info 6690] GRB 080925: Fermi GBM Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8291
SUBJECT: GRB 080925: Fermi GBM Detection
DATE:    08/09/27 05:56:47 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <avdhorst at science.uva.nl>

Adam Goldstein (UAH), Alexander van der Horst (NASA/ORAU) and Rob Preece
(UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team:

"At 18:35:55 UT on 25 September 2008, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located the bright GRB 080925 (trigger 244060556 /
080925.775). The on-ground calculated location, using the GBM trigger
data, is RA = 96.1, Dec = +18.2 (J2000 degrees, equivalent to 6h 24m,
+18d 12'), with a statistical uncertainty less than 1 degree (radius,
1-sigma containment) and an additional systematic error which is
currently estimated to be 2 to 3 degrees. The angle from the Fermi
Large Area Telescope (LAT) boresight is 38 degrees.

This GRB has several peaks, with T90 (50-300 keV) = 29 s and
T50 (50-300 keV) = 9 s. The time-averaged spectrum (8 keV-1 MeV)
from T0 to T0+16.6 s is best fit by a Band function with
Epeak = 120 +/- 5 keV, alpha = -0.53 +/- 0.05, and beta = -2.26 +/- 0.08.
The fluence (50-300 keV) is 9.7E-6 erg/cm^2.

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