GCN Circular 33510
Subject
Konus-Wind detection of GRB 230308A
Event
Date
2023-03-23T13:12:16Z (3 years ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:
The short-duration GRB 230308A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33420;
Malacaria et al., GCN Circ. 33440;
BALROG localization: Kunzweiler et al., GCN Circ. 33421;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33435;
CALET-GBM detection: Shimizu et al., GCN Circ. 33452;
IPN triangulation: Kozyrev et al., GCN Circ. 33477)
triggered Konus-Wind at T0=48749.809 s UT (13:32:29.809).
The burst light curve shows a multi-peaked structure
which starts at ~T0 and has a total duration of ~0.6 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/GRB230308_T48749/
As observed by Konus-Wind, the burst
had a fluence of 1.31(-0.14,+0.16)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0-2 ms,
of 8.03(-1.52,+1.61)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
The time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.29(-0.14,+0.17),
the high energy photon index beta = -3.22(-6.78,+0.76),
the peak energy Ep = 936(-162,+161) keV
(chi2 = 47/45 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.