GRB 090713

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."

T.Batsch, M.Cwiok, W.Dominik, G.Kasprowicz, A.Majcher, A.Majczyna,
K.Malek, L.Mankiewicz, K.Nawrocki, L.W.Piotrowski,
M.Siudek, M.Sokolowski, J.Uzycki, G.Wrochna, M.Zaremba, A.F.Zarnecki
on behalf of "Pi of the Sky" collaboration http://grb.fuw.edu.pl

The "Pi of the Sky" apparatus observed error box of Fermi GRB090713
before, during and after the burst, starting 20 minutes before the
Fermi trigger. No new source brighter than 11 mag has been identified
on 10s exposures.
IPN triangulation for this burst is strongly encouraged.