TITLE:   GCN CIRCULAR
NUMBER:  7995
SUBJECT: Konus-Wind observation of GRB 080721
DATE:    08/07/21 18:44:21 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

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

The bright GRB 080721 (Swift-BAT trigger #317508: Marshall et al., GCN
7988, Cummings et al., GCN 7992) triggered Konus-Wind at T0=37510.927 s 
UT (10:25:10.927).

The burst light shows multipeaked structure with a duration of ~30 s.

As observed by Konus-Wind the burst
had a fluence of 8.38(-0.60, +0.62)x10^-5 erg/cm2,
and a 64-ms peak flux measured from T0+9.648 s
of (1.96 +/- 0.31)x10^-5 erg/cm2/s
(both in the 20 keV - 5 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+23.808 s) is well fitted (in the 20 keV - 5 MeV range)
by GRBM (Band) model for which:
the low-energy photon index is alpha = -0.933(-0.084, +0.106),
the high energy photon index beta = -2.43(-0.42, +0.24),
the peak energy Ep = 485(-59, +67) keV (chi2 = 60.6/76 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/GRB080721_T37510/