TITLE:   GCN CIRCULAR
NUMBER:  37077
SUBJECT: Konus-Wind detection of GRB 240805A
DATE:    24/08/06 15:53:16 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 240805A
(Fermi-GBM observation: The Fermi GBM team, GCN 27031; Godwin et al., GCN 37075;
Swift-BAT detection: Dichiara et al., GCN 37032;
INTEGRAL IBIS/ISGRI detection: Mereghetti et al., GCN 37037; Götz et al., GCN 37041;
Fermi-LAT detection: Gupta et al., GCN 37042;
SVOM/GRM observation: Wang et al., GCN 37054)
triggered Konus-Wind at T0=7342.029 s UT (02:02:22.029).

The burst light curve shows a multipeaked structure
which starts at ~T0-2.3 s and has a total duration of ~15.6 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/GRB240805_T07342/

As observed by Konus-Wind, the burst
had a fluence of 3.43(-0.31,+0.35)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+3.680 s,
of 6.61(-1.44,+1.48)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+15.360 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.46(-0.11,+0.13),
the high energy photon index beta = -2.76(-0.43,+0.26),
the peak energy Ep = 272(-22,+22) keV
(chi2 = 81/80 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+7.168 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.51(-0.12,+0.14),
the high energy photon index beta = -2.78(-0.61,+0.29),
the peak energy Ep = 279(-26,+27) keV
(chi2 = 70/71 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.