TITLE:   GCN CIRCULAR
NUMBER:  36627
SUBJECT: Konus-Wind detection of GRB 240603A
DATE:    24/06/06 12:47:29 GMT
FROM:    Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The short-duration GRB 240603A
(GECAM-B detection: Wang & Xiong, GCN 36602;
Fermi-GBM detection: The Fermi GBM team, GCN 36608;
IPN triangulation: Kozyrev et al., GCN 36618)
triggered Konus-Wind at T0=8857.191 s UT (02:27:37.191).

The burst light curve shows a single pulse,
which starts at ~T0-0.3 s and has a total duration of ~1.1 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240603_T08857/

As observed by Konus-Wind, the burst
had a fluence of 3.81(-0.02,+0.84)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.504 s,
of 8.34(-2.03,+2.74)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since a significant fraction of the burst counts 
was detected before the trigger, the spectral analysis
was performed using the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.260 s to T0+0.784 s)
by a power law with exponential cutoff (CPL) model,
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -1.08(-0.68,+1.42) and Ep = 592(-82,+92) keV.

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