[vsnet-grb-info 7955] GRB 090608: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9498
SUBJECT: GRB 090608: Fermi GBM detection
DATE:    09/06/09 04:21:53 GMT
FROM:    Alexander van der Horst at NASA/MSFC  <Alexander.J.VanDerHorst at nasa.gov>

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

"At 01:15:26.60 UT on 8 June 2009, the Fermi Gamma-ray Burst Monitor
(GBM) triggered and located GRB 090608 (trigger 266116528 / 090608.052).
The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 100.2, Dec = -37.4 (J2000 degrees, equivalent to
J2000 6h41m, -37d25'), with a statistical 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 93 degrees.

The GBM light curve of this long and soft GRB consists of multiple peaks
and has a duration (T90) of 61 s (8-1000 keV). The time-averaged
spectrum from T0-18.4 to T0+20.5 s is adequately fit by a power law with
index = -1.83 +/- 0.07.
The fluence (8-1000 keV) in this interval is (3.2 +/- 0.1)E-6 erg/cm^2.
The 1-sec peak photon flux measured starting from T0+2.1s in the
8-1000 keV band is 2.7 +/- 0.1 ph/s/cm^2.

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