GCN Circular 14803

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

The long-duration intense hard-spectrum GRB 130606B
(Fermi-LAT detection: Vianello et al., GCN 14795
Not found
 
 
;
Fermi-GBM detection: Yu, GCN 14801
Not found
 
 
)
triggered Konus-Wind at T0=42940.544s UT (11:55:40.544).

The light curve shows a bright hard pulse complex from ~T0 to ~T0+70 s,
followed by a weak soft tail of emission out to ~T0+100s.
The emission at the main phase is seen up to ~17 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB130606_T42940/
Periodic `dips' visible in the 64-ms light curve are
due to the source occultation by the spacecraft.

As observed by Konus-Wind, the burst
had a fluence of (4.3 � 0.1)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+8.064s,
of (5.7 � 0.3)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+67.328 s)
is best fit in the 100 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.25 � 0.15,
the high energy photon index beta = -1.92 � 0.02,
the peak energy Ep = 337 � 59 keV,
chi2 = 120/81 dof.

The spectrum at the maximum count rate
(measured from T0+7.680 to T0+8.704 s)
is best fit in the 50 keV - 18 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.92 � 0.18,
the high energy photon index beta = -1.87 � 0.10,
the peak energy Ep = 690 � 240 keV,
chi2 = 96/90 dof.

All the quoted results are preliminary.