TITLE:   GCN CIRCULAR
NUMBER:  9344
SUBJECT: Konus-Wind observation of GRB 090510
DATE:    09/05/11 13:37:31 GMT
FROM:    Valentin Pal'shin at Ioffe Inst  <val@mail.ioffe.ru>

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

The short hard GRB 090510 (Swift-BAT trigger #351588: Hoversten et al.,
GCN 9331, Ukwatta et al., GCN 9337; Fermi-LAT trigger 263607783 / 
090510016: Ohno & Pelassa, GCN 9334) triggered Konus-Wind at T0=1381.547 
s UT (00:23:01.547).

The burst light curve shows a multipeaked structure with a duration of 
~0.4 s

As observed by Konus-Wind the burst
had a fluence of (2.42 +/- 0.37)x10^-5 erg/cm2,
and a 16-ms peak flux measured from T0+0.002 s
of (2.27 +/- 0.63)x10^-4 erg/cm2/s
(both in the 20 keV - 15 MeV energy range).

The spectrum of the most intense part
(from T0 to T0+0.192 s; it comprises ~75% of the total counts)
is well fitted (in the 20 keV - 15 MeV
range) by GRB (Band) model for which:
the low-energy photon index alpha = 0.11(-0.43, +0.48),
the high energy photon index beta = -1.61(-0.34, +0.15),
the peak energy E0 = 552(-249, +448) keV (chi2 = 28.6/31 dof).
Since beta > -2 we can establish only the lower limit on the peak energy 
  in the EF(E) spectrum: Ep > 912 keV.
The emission is clearly seen up to the end of the Konus-Wind energy 
range at 15 MeV.
All the quoted errors are at the 90% confidence level.

We note that since beta > -2 the bolometric fluence might be 
substantially higher than the given value.

The Konus-Wind light curve of this GRB is available
at http://www.ioffe.ru/LEA/GRBs/GRB090510_T01381/

[GCN OPS NOTE(11may09):  The typo in the Subject-line was changed from "091005"
to "090510".]