GCN Circular 15639

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

The long-duration GRB 131229A (Swift-BAT trigger 582374: Page et al., 
GCN 15627
Not found
 
 
) triggered Konus-Wind at T0=23970.560 s UT (06:39:30.560).

The burst light curve shows a multi-peaked structure with a total 
duration of ~17 s. The emission is seen up to ~1.5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB131229_T23970/

As observed by Konus-Wind, the burst had a
fluence of 2.45(-0.17,+0.18)x10-5 erg/cm2, and a 64-ms peak flux, 
measured from T0+10.976 s, of 1.07(-0.15,+0.15)x10-5 erg/cm2/s (both in 
the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+13.056 s) is best fit 
in the 20 keV - 1.5 MeV range by a power law with exponential cutoff 
model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
alpha = -0.65(-0.10,+0.11), and
Ep = 352(-28,+34) keV (chi2 = 51.9/60 dof).

The spectrum near the maximum count rate (measured from T0+8.448 to 
T0+13.056 s) is best fit in the 20 keV - 1.5 MeV range by a power law 
with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), 
alpha = -0.43(-0.10,+0.11), and
Ep = 366(-24,+28) keV (chi2 = 58.6/60 dof).

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