[vsnet-grb-info 17045] Konus-Wind observation of GRB 150911A

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18326
SUBJECT: Konus-Wind observation of  GRB 150911A
DATE:    15/09/17 04:21:46 GMT
FROM:    Anastasia Tsvetkova at Ioffe Institute  <tsvetkova at mail.ioffe.ru>

S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 150911A (Swift-BAT trigger #655262:
Starling, et al., GCN Circ. 18280; Markwardt , et al., GCN Circ. 18292)
was detected by Konus-Wind in the waiting mode.

The burst light curve shows a single pulse with a total duration of ~9 s.

As observed by Konus-Wind, the burst had a fluence of
3.13(-0.20,+0.26)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)+2.5 s, of 4.01(-0.32,+0.59)x10^-7 erg/cm2/s
(both in the 20 - 1000 keV energy range).

Fitting the K-W 3-channel time-integrated spectrum
(measured from ~T0(BAT)-0.5 s to ~T0(BAT)+8.5 s)
by a simple power-law model yields the photon index
-2.32(-0.09,+0.09), chi2=0.6/1 dof.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.

The K-W light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB150911A/

[GCN OPS NOTE(16sep15):  This circular was delayed  ~12 hours
in distribution because of an operation mistake at GCN.]