[vsnet-grb-info 14625] Konus-Wind observation of GRB 140306A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15939
SUBJECT: Konus-Wind observation of GRB 140306A
DATE:    14/03/07 12:17:50 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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 140306A (localized by IPN: Golenetskii et al., GCN 
15938; GBM detection: Fitzpatrick, GCN 15935) triggered Konus-Wind at 
T0=12581.686 s UT (03:29:41.686).

The burst light curve shows an bright multi-peaked pulse with
a duration of ~75 s. The emission is seen up to ~8 MeV.

As observed by Konus-Wind, the burst had a fluence of (1.35 +/- 
0.12)x10^-4 erg/cm2, and a 256-ms peak flux, measured from T0+4.592 s,
of (2.3 +/- 0.2)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+78.848 s)
is best fit (in the 20 keV - 15 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.21 (-0.04, 0.05)
and Ep = 1305 (-210,+273) keV (chi2 = 106/98 dof).
Fit with the GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.37 (chi2 = 106/97 dof).

The spectrum near the maximum count rate
(measured from T0 to T0+6.656 s)
is best fit (in the 20 keV - 15 MeV range)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.77 (-0.05, 0.05)
and Ep = 1524 (-142,+158) keV (chi2 = 76/98 dof).
Fit with the GRB (Band) model yields the same alpha and Ep,
and only an upper limit on the high energy
photon index: beta < -2.74 (chi2 = 76/97 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140306_T12581/

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