[vsnet-grb-info 6428] Konus-Wind observation of GRB 080727B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8042
SUBJECT: Konus-Wind observation of GRB 080727B
DATE:    08/07/28 12:43:57 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at 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 long GRB 080727B (Swift-BAT trigger #318101: Immler et al., GCN
8022, Baumgartner et al., GCN 8030) triggered Konus-Wind at T0=29609.825 
s UT (08:13:29.825).

The burst light curve shows two multipeaked pulses with a total duration 
of ~9 s.

As observed by Konus-Wind the burst
had a fluence of 9.46(-0.84, +0.98)x10^-6 erg/cm2,
and a 64-ms peak flux measured from T0+6.080 s
of 5.14(-0.10, +0.11)x10^-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+8.448 s) is well be 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 = -0.85(-0.18, +0.16),
and Ep = 282(-37, +52) keV (chi2 = 56.6/60 dof).
Fitting by GRBM (Band) model yields:
the low-energy photon index is alpha = -0.73(-0.24, +0.29),
the high energy photon index beta < -2.08,
the peak energy Ep = 242(-48, +69) keV (chi2 = 54.8/59 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/GRB080727_T29609/