TITLE:   GCN CIRCULAR
NUMBER:  15889
SUBJECT: Konus-Wind observation of GRB 140226A
DATE:    14/02/28 08:16:29 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long-duration GRB 140226A
(IPN trangulation: Hurley et al., GCN 15888),
which is a possible counterpart to the optical
transient source iPTF14yb (Cenko et al. GCN 15883),
was detected by Konus-Wind in the waiting mode
against the high solar particle background.

The light curve shows a single pulse, which peaked
at T0=36177 s UT (10:02:57) and had a duration of ~15 s.

As observed by Konus-Wind, the burst had a fluence of
(5.6 ± 1.1)x10^-6 erg/cm2 and a 2.944-s peak energy flux,
measured from T0 of (8.6 ± 1.7)x10^-7 erg/cm2
(both in the 20 - 10000 keV energy range).

Modeling the KW 3-channel time-integrated spectrum
(from T0-6.263 s to T0+5.513 s) by a power law
with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.1 ± 0.1, and Ep = 414 ± 79 keV.

All the quoted errors are estimated at 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/GRB140226A/