[vsnet-grb-info 7038] GRB 081204B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8622
SUBJECT: GRB 081204B: Fermi GBM detection
DATE:    08/12/05 15:48:57 GMT
FROM:    Elisabetta Bissaldi at MPE  <ebs at mpe.mpg.de>

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

"At 12:24:25.79 UT on 4 December 2008, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 081204B (trigger 250086266 / 081204517).
The on-ground calculated location, using the GBM trigger
data, is RA = 181.4, DEC = +32.1 (J2000 degrees,
equivalent to 12h 06m, 32d 06'), with an uncertainty
of 7.3 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 Fermi LAT boresight is 46 degrees.

This short GRB consists of a single pulse
with a duration (T90) of about 320 ms (8-1000 keV).
The time-averaged spectrum from T0-0.077 s to T0+0.115 s is
best fit by a simple power law function with
index -1.18 +/- 0.05 (chi squared 439 for 477 d.o.f.).
The event fluence (8-1000 keV) in this time interval is
(4.88 +/- 0.13)E-07 erg/cm^2. The peak photon flux
on the 64 ms timescale measured starting from T0-0.077 s
in the 8-1000 keV band is 16.3 +/- 0.6 ph/s/cm^2.

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