[vsnet-grb-info 15466] Konus-Wind observation of GRB 140825A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16755
SUBJECT: Konus-Wind observation of GRB 140825A
DATE:    14/08/29 17:23:14 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova at mail.ioffe.ru>

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, intense GRB 140825A
(IPN triangulation: Hurley et al., GCN 16752)
triggered Konus-Wind at T0=24925.66 s UT (06:55:25.660).

The burst light curve shows several peaks with a total duration of ~14 s.
The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.7(-0.2,+0.2)x10^-5 erg/cm2,
and a 64-ms peak energy flux, measured from T0+1.984 s,
of 1.4(-0.2,+0.2)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum of the burst
(measured from T0 to T0+10.752 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.94(-0.07,+0.08),
the high-energy photon index beta = -3.42(-1.36,+0.40),
the peak energy Ep = 142(-7,+7) keV,
chi2 = 86/84 dof.

The spectrum near the peak count rate
(measured from T0+2.048 to T0+2.560 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.44(-0.15,+0.21),
the high-energy photon index beta = -3.42(-1.61,+0.59),
the peak energy Ep = 208(-23,+18) keV,
chi2 = 41/44 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140825_T24925/

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