[vsnet-grb-info 5061] Konus-Wind observation of GRB 070824

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6768
SUBJECT: Konus-Wind observation of GRB 070824
DATE:    07/08/31 12:05:53 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks,
and T. Cline on behalf of the Konus-Wind team:

The bright long GRB 070824 localized by SuperAGILE/IPN
(Donnarumma et al., GCN 6767) triggered Konus-Wind
at T0=74999.585 s UT (20:49:59.585).

The Konus-Wind light curve shows two pulses
with a total duration of ~12 s.

As observed by Konus-Wind the burst
had a fluence of 2.84(-0.26, +0.09)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+8.368 s
of 2.85(-0.38, +0.29)x10^-5 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 s to T0+16.986 s) is well fitted
(in the 20 keV - 2 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep)
with alpha = 1.051 (-0.081, +0.078)
and Ep = 253 (-19, +22) keV (chi2 = 66.2/60 dof).
Fitting by a GRBM (Band) model yields:
the low-energy photon index alpha = -1.025 +/- 0.084,
the high energy photon index beta < -2.55,
the peak energy Ep = 243(-20, +24) keV (chi2 = 64.5/59 dof).

All the quoted errors are at the 90% confidence level.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.rssi.ru/LEA/GRBs/GRB070824_T74999/