[vsnet-grb-info 12907] Konus-Wind observation of GRB 130219A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14250
SUBJECT: Konus-Wind observation of GRB 130219A
DATE:    13/02/22 11:01:58 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long-duration intense GRB 130219A
(Fermi GBM detection: Collazzi, GCN 14243;
IPN detection and localization: Hurley et al., GCN 14246)
triggered Konus-Wind at T0=66950.352.048s UT (18:35:50.352)

The burst started with a soft precursor
at ~T0-0.5s which was followed, after ~65 sec of quiescence,
by a harder intense emission pulse.
A total duration of the burst is ~117 s.
The emission in the main emission episode is seen up to ~8 MeV.

As observed by Konus-Wind, the burst
had a fluence of (4.2 ± 0.4)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+81.152 s,
of (2.4 ± 0.2)x10-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The energy spectrum of the precursor (measured T0 to T0+8.444 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model,
for which:
alpha = +0.11 ± 0.45,
and Ep = 95 ± 8 keV,
chi2 = 57.2/60 dof.

The time-integrated spectrum of the main emission episode
(measured T0+67.792 to T0+105.984 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.08 ± 0.07,
the high energy photon index beta = -2.12 ± 0.11,
the peak energy Ep = 280 ± 35 keV,
chi2 = 90.8/96 dof.

The spectrum at the maximum count rate
(measured T0+79.984 to T0+81.408 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.10 ± 0.05,
the high energy photon index beta = -3.1 ± 0.2,
the peak energy Ep = 365 ± 15 keV,
chi2 = 81.3/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130219_T66950/

All the quoted results are preliminary.