TITLE:   GCN CIRCULAR
NUMBER:  37173
SUBJECT: Konus-Wind detection of GRB 240811A
DATE:    24/08/13 11:13:37 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 long-duration GRB 240811A
(Swift detection: Page & Gupta, GCN 37136; Lien et al., GCN 37155)
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data in the 20-300 keV band
reveals a >18 sigma count rate increase in the interval
from T0-34.908 s to T0+35.748 s where T0 = T0(BAT) = 14:07:33.190 UT.

The KW light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB240811A/

Modeling a time-integrated spectrum of the burst
(from T0-34.908 s to T0+35.748 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep):
yields alpha = -1.22 (-0.27, + 0.80) and Ep = 126(-33,+51) keV.

The total burst fluence is 4.65(-0.30,+1.35)x10^-6 erg/cm^2,
and the 2.944 s peak energy flux, measured from T0+3.364 s,
is 2.43(-0.33,+0.76)x10^-7 erg/cm^2.
(both in the 20 keV - 10 MeV energy range).

All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.