[vsnet-grb-info 4179] Konus-Wind observation of GRB 061222A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5984
SUBJECT: Konus-Wind observation of GRB 061222A
DATE:    06/12/27 14:29:39 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val at mail.ioffe.ru>

The most intense part of the long GRB 061222A(Swift-BAT trigger
#252588; Grupe et al., GCN 5954; Tueller et al., GCN 5964)
triggered Konus-Wind at T0=12614.682 s UT (03:30:14.682).
The emission is clearly seen in the Konus-Wind data
starting at T-T0~-80 s.

As observed by Konus-Wind the burst had a duration of ~100 s,
fluence 2.66(-0.23, +0.43)x10^-5 erg/cm2,
the 64-ms peak flux measured from T0+5.312 s
5.65(-1.19, +1.42)x10^-6  erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The spectrum integrated over the most intense part of the burst
(from T0 to T0+15.104 s) is well fitted (in the 20 keV - 2 MeV range)
by GRBM (Band) model for which:
the low-energy photon index is alpha = -0.94(-0.13, +0.14),
the high energy photon index beta = -2.41(-1.21, +0.28),
the peak energy Ep = 283(-42, +59) keV (chi2 = 64/60 dof).
The fitting by a power law with exponential cutoff model:
dN/dE ~ E^(-alpha)*exp(-E*(2-alpha)/Ep)
in the same energy range yields
alpha = 1.02(-0.11, +0.10)
and Ep = 324(-41, +54) keV (chi2 = 67/61 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/GRB061222_T12614/