[vsnet-grb-info 27625] Konus-Wind detection of GRB 210324C

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29728
SUBJECT: Konus-Wind detection of GRB 210324C
DATE:    21/03/25 18:42:58 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred at mail.ioffe.ru>

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

The long GRB 210324C (IPN triangulation:  Hurley et al., GCN 29727)
triggered Konus-Wind (KW) at T0=72000.034 s UT (20:00:00.034).

The burst light curve shows a multi-peaked structure with the total 
duration of ~75 s.
The emission is seen up to ~10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB210324_T72000/

As observed by Konus-Wind, the burst had
a fluence of (7.0 ± 0.6)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0+34.112,
of (3.4 ± 0.4)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+65.024 s)
is best fit in the 20 keV - 20 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.51 (-0.10,+0.11),
the high energy photon index beta = -2.69 (-0.28,+0.18),
the peak energy Ep = 190 (-11,+12) keV,
chi2 = 97/97 dof.

The spectrum near the peak count rate (measured from T0+33.024
to T0+40.448 s) is best fit in the 20 keV - 20 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.56 (-0.15,+0.17),
the high energy photon index beta = -2.64 (-0.53,+0.24),
the peak energy Ep = 211 (-21,+26) keV,
chi2 = 108/97 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.