GCN Circular 17427

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 150206A
(Swift BAT trigger 630019: Hagen et al., GCN 17413
Not found
 
 
;
Barthelmy  et al., GCN 17426
Not found
 
 
;
MAXI/GSC detection: Negoro et al., GCN 17414
Not found
 
 
)
triggered Konus-Wind at T0=52280.265 s UT (14:31:20.265).

The burst light curve shows a broad, multi-peaked pulse
with a total duration of ~60 s.
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/GRB150206_T52280/

As observed by Konus-Wind, the burst
had a fluence of 5.52(-0.64,+0.69)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+4.320 s,
of 7.92(-1.78,+1.83)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+32.256 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.73(-0.14,+0.18),
the high energy photon index beta = -2.20(-0.22,+0.15),
the peak energy Ep = 228(-35,+37) keV
(chi2 = 74/97 dof)

The spectrum near the maximum count rate
(measured from T0 to T0+7.680 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.48(-0.17,+0.21),
the high energy photon index beta = -2.20(-0.22,+0.15),
the peak energy Ep = 242(-35,+38) keV
(chi2 = 84/90 dof)

Assuming the redshift z=2.087 (Kruehler et al., GCN 17420
Not found
 
 
)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, and Omega_Lambda = 0.73,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 6.0(-0.7,+0.8)x10^53 erg,
the peak luminosity L_iso is 2.7(-0.6,+0.6)x10^53 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is 703(-109,+114) keV.

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