[vsnet-grb-info 6677] GRB 080913B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8280
SUBJECT: GRB 080913B:  Fermi GBM detection
DATE:    08/09/21 15:32:20 GMT
FROM:    Bill Paciesas at UAH  <bill.paciesas at nasa.gov>

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

"At 17:38:31 UT on 13 September 2008, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 080913B (trigger 243020312 / 080913.735).
The on-ground calculated location, using the GBM trigger data,
is RA = 46.3, Dec = -4.6 (J2000 degrees) (equivalent to J2000 3h 05m,
-4d 36'), with an uncertainty of 3.3 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 71 degrees.

This GRB was about 140 s long consisting of several peaks with a main
emission period of 30 seconds.  The time-averaged spectrum from T-2 to T+28 s 
is best fit by a power law with exponential cut-off,
with a power-law index of -0.69 +/- 0.16 and a cut-off energy, parameterized as 
Epeak, of 114 +/- 14 keV. The fluence between 50 and 300 keV over these 30 seconds 
is (2.2 +/- 0.5) x 10^-6 erg/cm^2.

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