GCN Circular 15398
Subject
Konus-Wind observation of GRB 131028A
Date
2013-10-29T15:50:06Z (11 years ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin,
P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf
of the Konus-Wind team, report:
The bright, long-duration, hard-spectrum GRB 131028A
(Fermi GBM detection: von Kienlin, GCN 15396;
IPN triangulation: Hurley at al., GCN 15397)
triggered Konus-Wind at T0=6546.966 s UT (01:49:06.966).
The burst light curve shows a bright, hard pulse from ~T0 to ~T0+20 s,
followed by a tail of softer emission in next ~50 s.
The emission in the main pulse is seen up to ~10 MeV.
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB131028_T06546/
As observed by Konus-Wind, the burst
had a fluence of (2.41 � 0.05)x10-4 erg/cm2,
and a 64-ms peak flux, measured from T0+5.760 s,
of (6.6 � 0.3)x10-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum (measured from T0 to T0+20.736 s)
is best fit in the 50 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.82 � 0.02,
the high energy photon index beta = -3.07 � 0.17,
the peak energy Ep = 901 � 25 keV,
chi2 = 97.2/93 dof.
The spectrum near the maximum count rate
(measured from T0+5.376 s to T0+6.400 s)
is best fit in the 50 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.56 � 0.06,
the high energy photon index beta = -3.18 � 0.42,
the peak energy Ep = 1277 � 91 keV,
chi2 = 119/86 dof.
All the quoted values are preliminary.