GCN Circular 10882

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 GRB 100621A (Swift-BAT trigger=425151;
Ukwatta et al., GCN 10870
Not found
 
 
; Ukwatta et al., GCN 10875
Not found
 
 
)
triggered Konus-Wind at T0=11013.352s UT (03:03:33.352)

The burst light curve shows multiple overlapping peaks
with a total duration of ~80 s.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB100621_T11013/

As observed by Konus-Wind the burst
had a fluence of 3.6(+/-0.4)x10-5 erg/cm2,
and a 256-ms peak flux measured from T0+26.880s
of 1.70(+/-0.13)x10-6 erg/cm2/s
(both in the 20 keV - 2 MeV energy range).

The time-integrated spectrum of the burst
(from T0 to T0+73.984 s) is best fit
in the 20 keV - 2 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -1.70 (+/-0.13),
the high energy photon index beta = -2.45 ( <-2.3 ),
the peak energy Ep = 95(-13, +18)keV (chi2 = 65/57 dof).

The spectrum at the maximum count rate
(measured from T0+24.832 to T0+33.024 s) is best fit
in the 20 keV - 2 MeV range by the GRB (Band)
model, for which:
the low-energy photon index alpha = -1.15 (-0.2/+0.3),
the high energy photon index beta = -2.8 (-0.7/+0.3),
the peak energy Ep = 83(+/-9)keV (chi2 = 64/57 dof).

Assuming z=0.542 (Milvang-Jensen et al., GCN 10876
Not found
 
 
) and
a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.27, Omega_Lambda = 0.73,
the isotropic energy release E_iso = 2.8(+/-0.3)x10^52 erg,
the peak luminosity (L_iso)_max = (2.04+/-0.16)x10^51 erg/s.

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