Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 16673

Konus-Wind observation of GRB 140808A
2014-08-09T14:54:50Z (10 years ago)
Dmitry Svinkin at Ioffe Institute <>
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:

A long-duration GRB 140808A
(Fermi-GBM detection: Zhang, GCN Circ. 16669)
triggered Konus-Wind at T0=3239.264 s UT (00:53:59.264).

The burst light curve shows two emission episodes, the first,
reported in GCN 16669, from ~T0-1.9 s to ~T0+3.6 s,
and the second, from ~T0+303 s to ~T0+336 s.
The second episode is also seen in the INTEGRAL (SPI-ACS) data but
it can't be unambiguously attributed to the GRB by the triangulation,
so far. The total duration of the burst is ~338 s.

The emission is seen up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at

As observed by Konus-Wind, the first episode
had a fluence of 3.12(-0.30,+0.33)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.312 s,
of 1.6(-0.4,+0.4)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the first episode
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.95 (-0.26,+0.29)
and Ep = 127 (-18,+25) keV (chi2 = 91/78 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 90/77 dof)

The second episode had a fluence of 4.2(-1.2,+4.0)x10^-6 erg/cm2,
in the 20 keV - 10 MeV energy range.

The time-averaged spectrum of this episode
(measured from T0+303.36 to T0+336.128 s)
is best fit in the 20 keV - 5 MeV range
by the power law with exponential cutoff model
with  alpha = -1.22 (-0.37,+0.48)
and Ep = 376 (-158,+1558) keV (chi2 = 82/88 dof).

Assuming the second episode is related to the GRB the total fluence
is 7.3(-1.2,+4.0)x10^-6 erg/cm2. From the redshift z=3.29
(Gorosabel et al., GCN Circ. 16671)
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 ~1.7x10^53 erg,
the peak luminosity L_iso is ~3.8x10^52 erg/s.

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
Looking for U.S. government information and services? Visit