[vsnet-grb-info 6905] GRB 081105B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8495
SUBJECT: GRB 081105B: Fermi GBM detection
DATE:    08/11/07 17:01:51 GMT
FROM:    Andreas von Kienlin at MPE  <azk at mpe.mpg.de>

Elisabetta Bissaldi (MPE) and A. von Kienlin (MPE) 
report on behalf of the Fermi GBM Team: 

"At 14:43:51.29 UT on 05 November 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081105B (trigger 247589032 / 081105614).
The on-ground calculated location, using the GBM trigger 
data, is RA = 215.7 deg, Dec = 42.8 (J2000 degrees, 
equivalent to 14h 23m, 42d 48'), with an uncertainty 
of 12 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 87 degrees.

This short GRB consists of a single peak with an estimated
T90 (8-1000 keV) of 180 ms and T50 (8-1000 keV) of 64 ms.
The spectral fit to this weak event is poorly constrained.
A fit of the time-averaged spectrum from T0-0.067 s to T0-0.019 s  
by a simple power law function yields an index of -1.17 +/- 0.05 
(chi squared 311 for 421 d.o.f.).
The event fluence (8-1000 keV) in this time interval is 
(2.28 +/- 0.11)E-07 erg/cm^2. The photon flux on the 
16 ms timescale measured starting from T0-0.067 s 
in the 8-1000 keV band is 20 +/- 3 ph/s/cm^2. 

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