TITLE:   GCN CIRCULAR
NUMBER:  14542
SUBJECT: Konus-Wind observation of GRB 130502B
DATE:    13/05/03 14:32:02 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@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 130502B
(Fermi-GBM detection: von Kienlin et al., GCN 14530;
Fermi-LAT detection: Kocevski et al., GCN 14532)
triggered Konus-Wind at T0=28272.763s UT (07:51:12.763)

The light curve shows a bright multi-peaked structure
from ~T0 s to ~T0+30s.
The emission is seen up to 10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130502_T28272/

As observed by Konus-Wind, the burst
had a fluence of (1.13 ± 0.04)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+29.944s,
of (1.81 ± 0.08)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+27.392 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 = -0.84 ± 0.04,
the high energy photon index beta = -2.7 ± 0.1,
the peak energy Ep = 293 ± 9 keV,
chi2 = 107/91 dof.

The spectrum at the maximum count rate
(measured from T0+26.624 to T0+27.392 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 = -0.81 ± 0.06,
the peak energy Ep = 264 ± 14 keV,
chi2 = 104/93 dof.

All the quoted results are preliminary.