[vsnet-grb-info 8128] GRB 090713: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9661
SUBJECT: GRB 090713: Fermi GBM detection
DATE:    09/07/13 15:20:47 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 00:29:28.06 UT on 13 July 2009, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 090713 (trigger 269137770 / 090713020).
The on-ground calculated location, using the GBM trigger data, is
RA = 284.8, Dec = -3.3 (J2000 degrees, equivalent to 18h59m, -3d20'),
with an uncertainty of 2.4 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 63 degrees.

The GBM light curve consists of multiple peaks with a duration (T90)
of about 113 s (8-1000 keV).
The time-averaged spectrum from T0-4.1 s to T0+55.3 s is well fit by
a power law function with an exponential high energy cutoff. The
power-law index is -0.34 +/- 0.12 and the cutoff energy, parameterized
as Epeak, is 99 +/- 5 keV (chi squared 339 for 359 d.o.f.).

The event fluence (8-1000 keV) in this time interval is (3.7 +/- 0.4)E-6
erg/cm^2. The 1-sec peak photon flux measured starting from T0+24.6 s
in the 8-1000 keV band is 1.6 +/- 0.2 ph/s/cm^2.

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