TITLE:   GCN CIRCULAR
NUMBER:  38297
SUBJECT: Konus-Wind detection of GRB 241120A
DATE:    24/11/22 14:38:03 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 241120A
(Fermi-GBM detection: Fermi GBM team, GCN 38279;
Hamburg & Meegan, GCN 38285;
INTEGRAL (IBIS/ISGRI) detection: Gotz et al., GCN 38280;
CALET (CGBM) detection: Cherry et al., GCN 38295)
triggered Konus-Wind at T0=21240.717 s UT (05:54:00.717).

The burst light curve shows a single pulse,
which starts at ~T0-1.9 s and has a total duration of ~2.9 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB241120_T21240/

As observed by Konus-Wind, the burst
had a fluence of 3.55(-0.48,+0.59)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.372 s,
of 4.98(-1.17,+1.30)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+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 = -0.91(-0.29,+0.34)
and Ep = 267(-56,+95) keV (chi2 = 80/78 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.6
(chi2 = 80/77 dof).

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