[vsnet-grb-info 20770] Konus-Wind observation of GRB 180626C

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22868
SUBJECT: Konus-Wind observation of GRB 180626C
DATE:    18/06/28 11:22:16 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova at mail.ioffe.ru>

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

The short-duration GRB 180626C
(IPN triangulation: Svinkin et al., GCN 22864)
triggered Konus-Wind at T0=33832.424 s UT (09:23:52.424).

The burst light curve shows a single pulse
which starts at T0-40 ms and has a total duration of ~340 ms.

As observed by Konus-Wind, the burst
had a fluence of 6.13(-1.15,+2.18)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.032 s,
of 7.87(-2.06,+3.15)x10^-6 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 T0-0.04 s to T0+0.336 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.87 (-0.23,+0.31), and Ep = 406 (-113,+225) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180626_T33832/

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