[vsnet-grb-info 19447] Konus-Wind observation of GRB 170529A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21167
SUBJECT: Konus-Wind observation of GRB 170529A
DATE:    17/05/30 16:22:19 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova at mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 170529A
(IPN triangulation: Hurley et al., GCN 21165)
triggered Konus-Wind at T0=25541.567 s UT (07:05:41.567).

The burst light curve shows two separate multipeaked episodes: the first
from ~T0-6 s to ~T0+52 s and the second weaker/softer
from ~T0+176 s to ~T0+220 s. The total duration of the burst is ~226 s.
The emission is seen up to 20 MeV.

As observed by Konus-Wind, the burst
had a fluence of 1.73(-0.40,+0.62)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+7.504 s,
of 1.54(-0.27,+0.28)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+222.464 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.96(-0.16,+0.46),
the high energy photon index beta = -2.23(-1.36,+0.41),
the peak energy Ep = 422(-188,+142) keV
(chi2 = 89/98 dof).

The spectrum near the maximum count rate
(measured from T0+6.656 to T0+11.008 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.49(-0.10,+0.11),
the high energy photon index beta = -2.41(-0.28,+0.18),
the peak energy Ep = 486(-54,+59) keV
(chi2 = 75/87 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB170529_T25541/

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