[vsnet-grb-info 13228] Konus-Wind observation of GRB 130504B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14565
SUBJECT: Konus-Wind observation of GRB 130504B
DATE:    13/05/05 09:20:24 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 short-duration hard GRB 130504B
(Fermi-GBM detection: von Kienlin, GCN 14560;
IPN triangulation: Golenetskii et al., GCN 14561)
triggered Konus-Wind at T0=27119.723s UT (07:31:59.723)

The light curve shows a double-peaked structure
from ~T0-0.064 s to ~T0+0.368s.
The total duration of the burst is ~0.430 s
The emission is seen up to ~8 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130504_T27119/

As observed by Konus-Wind, the burst
had a fluence of (9.3 ± 0.9)x10-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.320s,
of (5.0 ± 0.9)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The spectrum of the burst (measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 15 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -0.50 ± 0.13,
the peak energy Ep = 980 ± 125 keV,
chi2 = 40/36 dof.

All the quoted results are preliminary.