GCN Circular 17911

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

The long-duration GRB 150607A (Swift-BAT trigger #642620:
D'Elia, et al., GCN 17904
Not found
 
 
; Palmer, et al., GCN 17907
Not found
 
 
;
Fermi GBM detection: Roberts, GCN 17906
Not found
 
 
) triggered Konus-Wind at 
T0=28509.211 s UT (07:55:09.211).

The burst light curve shows a multipeak structure
with a total duration of ~30 s.
The emission is seen up to ~1 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB150607_T28509/

As observed by Konus-Wind, the burst
had a fluence of 4.2(-0.8,+1.3)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0-0.222 s,
of 1.2(-0.5,+0.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+33.024 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.4(-0.3,+0.4)
and Ep = 173(-57,+183) keV (chi2 = 61/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2
(chi2 = 60/61 dof)

The spectrum near the maximum count rate
(measured from T0+0.000 to T0+8.448 s)
is best fit in the 20 keV - 2 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.4(-0.3,+0.4)
and Ep = 152(-42,+108) keV (chi2 = 46/62 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2
(chi2 = 46/61 dof)

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