[vsnet-grb-info 20456] Konus-Wind observation of GRB 180317A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22552
SUBJECT: Konus-Wind observation of GRB 180317A
DATE:    18/03/27 11:31:50 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, hard-spectrum GRB 180317A
(IPN triangulation: Svinkin et al., GCN 22521)
triggered Konus-Wind at T0=61287.097 s UT (17:01:27.097).

The burst light curve shows a single pulse
which starts at T0-34 ms and has a total duration of ~74 ms.

As observed by Konus-Wind, the burst
had a fluence of 9.47(-2.14,+6.93)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.024 s,
of 2.69(-0.71,+2.00)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the most intense part of the burst was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modeling the KW 3-channel time-integrated spectrum
(from T0-0.034 s to T0+0.040 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.74(-0.36,+0.51), and Ep = 757(-253,+1050) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180317_T61287/

The burst is not seen in the waiting mode data.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.