[vsnet-grb-info 15370] Konus-Wind observation of GRB 140801A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16660
SUBJECT: Konus-Wind observation of GRB 140801A
DATE:    14/08/02 12:26:02 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long-duration GRB 140801A
(IPN triangulation: Hurley et al., GCN 16655;
Fermi-GBM detection: Pelassa, GCN 16658)
triggered Konus-Wind at T0=68394.769 s UT (18:59:54.769).

The light curve shows a multi-peaked structure with a total duration of ~7.5 s.
The emission is seen up to ~3 MeV.

As observed by Konus-Wind, the burst had a fluence
of 1.10(-0.04,+0.04)x10^-5 erg/cm2, and a 64-ms peak flux,
measured from T0+0.128 s, of 4.6(-0.6,+0.6)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum (measured from T0 to T0+7.680 s)
is best fit in the 20 keV - 5 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = -0.44(-0.17,+0.18),
and the peak energy Ep = 108(-4,+5) keV,
chi2 = 75/71 dof.
Fitting this spectrum with the Band model yields the same
values of alpha and Ep with an upper limit on beta of -4.2

The spectrum near the peak count rate (measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 5 MeV range
by the cutoff power law with the following model parameters:
the photon index alpha = +0.38(-0.56,+0.69),
and the peak energy Ep = 121(-12,+13) keV,
chi2 = 27/24 dof.

Assuming the redshift z=1.320 (de Ugarte Postigo et al., GCN 16657)
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 ~4.9x10^52 erg,
the peak luminosity L_iso is ~5.0x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i, is ~250 keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB140801_T68394/

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