[vsnet-grb-info 15034] Konus-Wind observation of GRB 140523A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16328
SUBJECT: Konus-Wind observation of GRB 140523A
DATE:    14/05/24 15:57:50 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long-duration, intense GRB 140523A
(Fermi-GBM detection: Stanbro, GCN 16319;
Fermi-LAT detection: von Kienlin and Connaughton, GCN 16321;
IPN triangulation: Golenetskii et al., GCN 16327)
triggered Konus-Wind at T0=11157.811 s UT (03:05:57.811).

The light curve shows a multi-peaked structure with total duration
of ~22 s. The emission is seen up to ~7 MeV.

As observed by Konus-Wind, the burst had a fluence
of 5.5(-0.4,+0.4)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+0.640 s, of 1.6(-0.1,+0.1)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst (measured from T0 to T0+27.648 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 = -1.22 (-0.09,+0.10),
the high energy photon index beta = -2.7 (-0.4,+0.2),
the peak energy Ep = 212 (-17,+18) keV,
chi2 = 118/97 dof.

The spectrum near the peak count rate (measured from T0 to T0+4.864 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 = -0.58 (-0.14,+0.16),
the high energy photon index beta = -2.7 (-0.4,+0.2),
the peak energy Ep = 287 (-26,+29) keV,
chi2 = 100/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140523_T11157/

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