TITLE:   GCN CIRCULAR
NUMBER:  35659
SUBJECT: Konus-Wind detection of GRB 240124B
DATE:    24/02/02 15:58:30 GMT
FROM:    Alexandra Lysenko at Ioffe Institute <alexandra.lysenko@mail.ioffe.ru>

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

The long-duration GRB 240124B
(AstroSat CZTI detection: Joshi et al., GCN 35636;
IPN triangulation: Ridnaia et al., GCN 35657)
triggered Konus-Wind at T0=76473.999 s UT (21:14:33.999).

The burst light curve shows a single-pulse structure
which starts at ~T0-1.1 s and has a total duration of ~4.0 s.
The emission is seen up to 3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240124_T76473/

As observed by Konus-Wind, the burst
had a fluence of 4.57(-0.85,+2.93)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.228s,
of 4.33(-1.37,+3.93)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

A time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.40(-0.35,+0.44)
and Ep = 270(-94,+1040) keV (chi2 = 113/97 dof).
Fitting by a GRB (Band) model yields close alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.9
(chi2 = 112/96 dof).

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