GCN Circular 15368
Subject
Konus-Wind observation of GRB 131011B
Event
Date
2013-10-24T17:52:37Z (12 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 long-duration GRB 131011B
(Swift-BAT trigger 574266: Beardmore, et al., GCN 15323;
IPN triangulation: Hurley at al., GCN 15366)
triggered Konus-Wind at T0=80208.914 s UT (22:16:48.914).
The burst light curve shows a broad multi-peaked pulse from ~T0-35 s
till ~T0+40 s.
The emission is seen up to ~12 MeV.
The K-W ecliptic latitude response indicates the source located
at medium-to-high Northern ecliptic latitude,
which is at odds with the BAT position reported in GCN 15323,
however, consistent with the recent IPN box (GCN 15366).
The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB131014_T80208/
As observed by Konus-Wind, the burst
had a fluence of (7.7 � 0.3)x10-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.212 s,
of (6.0 � 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+31.744 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.68 � 0.06,
the high energy photon index beta = -2.21 � 0.09,
the peak energy Ep = 270 � 18 keV,
chi2 = 110/97 dof.
The spectrum near the maximum count rate
(measured from T0 to T0+7.936 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.63 � 0.04,
the high energy photon index beta = -2.22 � 0.14,
the peak energy Ep = 331 � 33 keV,
chi2 = 131/97 dof.
All the quoted values are preliminary.