[vsnet-grb-info 20652] Konus-Wind observation of GRB 180529A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22750
SUBJECT: Konus-Wind observation of GRB 180529A
DATE:    18/05/31 14:18:43 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin at mail.ioffe.ru>

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

The short-duration, bright GRB 180529A
(AGILE-MCAL detection: Ursi et al., GCN Circ. 22741;
IPN triangulation: Hurley et al., GCN Circ. 22748;
CALET-CGBM detection: Onozawa et al., GCN Circ. 22749)
triggered Konus-Wind at T0=30554.458 s UT (08:29:14.458).

The burst light curve shows a multi-peaked structure
which starts at ~T0-0.5 s and has a total duration of ~1.7 s.
The emission is seen up to ~6 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180529_T30554/

As observed by Konus-Wind, the burst
had a fluence of 1.08(-0.22,+0.30)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.446 s,
of 1.65(-0.61,+0.71)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+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.71(-0.21,+0.26)
and Ep = 1046(-295,+502) keV (chi2 = 99/84 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.3
(chi2 = 99/83 dof).

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