GCN Circular 37079

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

The long GRB 240802A (AstroSat CZTI detection: Waratkar et al., GCN 37018
Not found
 
 
;
SVOM/GRM observation: Wang et al., GCN 37022
Not found
 
 
;
IPN triangulation: Svinkin et al., GCN 37026
Not found
 
 
; Kozyrev et al., GCN 37078
Not found
 
 
),
associated with the fast X-ray transient EP240802a (Wang et al., GCN 37019
Not found
 
 
;
Aryan et al., GCN 37021
Not found
 
 
; Svinkin et al., GCN 37026
Not found
 
 
; Kozyrev et al., GCN 37078
Not found
 
 
),
triggered Konus-Wind (KW) at T0=38048.482 s UT (10:34:08.482).

The burst light curve shows a multi-peaked emission pulse,
which starts at ~T0-13 s and has the total duration of ~47 s.
Two main peaks in the light curve are located around ~T0 and ~T0+29 s,
respectively.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB240802_T38048/

As observed by Konus-Wind, the burst had the total fluence
of 1.63(-0.14,+0.15)x10^-5 erg/cm^2 and a 2.944-s peak energy flux,
measured from T0+0.032 s, of 8.21(-2.63,+3.09)x10^-6 erg/cm^2/s
(both in the 20 keV - 10 MeV energy range).

Due to telemetry errors in the KW triggered-mode spectra, the spectral analysis
was performed using the 3-channel waiting-mode count rates.
Modeling the time-integrated spectrum (measured from T0-13.161 s to T0+33.943 s)
by a power law with exponential cutoff (CPL) function dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -1.38(-0.11, + 0.12) and Ep = 226(-36,+51) keV.
A CPL fit to the spectrum near the peak count rate (measured from T0-1.385 s to T0+1.559 s)
results in alpha = -1.02(-0.15,+0.17) and Ep = 273(-42,+55) keV.

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