[vsnet-grb-info 7125] Konus-Wind observation of very bright GRB 081215A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8706
SUBJECT: Konus-Wind observation of very bright GRB 081215A
DATE:    08/12/22 16:19:07 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 very bright GRB 081215A (Fermi/GBM trigger 251059717 / 081215784: 
Preece, GCN 8678, 8679) localized by IPN (Golenetskii et al., GCN 8702) 
triggered Konus-Wind at T0=67721.281 s UT (18:48:41.281).

As observed by Konus-Wind the burst
had a fluence of (7.99 +/- 0.68)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.448 s
of (1.24 +/- 0.17)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+12.544 s) is well be fitted (in the 20 keV - 5 MeV
range) by GRB (Band) model for which:
the low-energy photon index is alpha = -0.870(-0.064, +0.070),
the high energy photon index beta = -2.20(-0.19, +0.13),
the peak energy Ep = 447(-52, +60) keV (chi2 = 72.2/76 dof).
The spectrum of the most intense peak
(from T0+0.256 s to T0+0.512 s) is well fitted (in the 20 keV-10 MeV
range) by GRB (Band) model for which:
the low-energy photon index is alpha = -0.49(-0.10, +0.12),
the high energy photon index beta = 2.38(-0.37, +0.23),
the peak energy Ep = 1001(-174, +193) keV (chi2 = 57.5/58 dof).
In this spectrum a statistically significant emission is clearly seen up 
to 10 MeV.

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