GCN Circular 46173
Subject
Konus-Wind detection of GRB 261024D
Event
Date
2026-11-06T14:43:27Z (7 hours ago)
From
Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru>
Via
Web form
D. Svinkin, D. Frederiks, A. Lysenko, V. Panteleeva, A. Ridnaia,
A. Tsvetkova, M. Ulanov, and T. Cline
on behalf of the Konus-Wind team, report:
The long-duration GRB 261024D
(AstroSat-CZTI detection: Goyal et al., GCN 46040;
NuSTAR-ACS detection: Waratkar et al., GCN 46051;
Glowbug detection: Cheung et al., GCN 46053;
GECAM-B detection: Luo et al., GCN 46061;
Insight-HXMT-HE detection: Luo et al., GCN 46065;
IPN triangulation: Kozyrev et al., GCN 46094;
SVOM-GRM detection: Luo et al., GCN 46111)
triggered Konus-Wind at T0=77582.529 s UT (21:33:02.529).
The burst light curve shows a multipeaked structure
which starts at ~T0-0.6 s and has a total duration of ~11 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/GRB261024_T77582/
As observed by Konus-Wind, the burst
had the total fluence of 1.43(-0.06,+0.07)x10^-5 erg/cm2,
and the 64-ms peak flux, measured from T0+1.664 s,
of 4.92(-0.56,+0.56)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+14.592 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.76(-0.08,+0.08),
the high energy photon index beta = -3.44(-0.70,+0.32),
the peak energy Ep = 121(-4,+4) keV
(chi2 = 115/97 dof).
The spectrum near the maximum count rate
(measured from T0+0.256 to T0+6.400 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.52(-0.10,+0.11),
the high energy photon index beta = -2.92(-0.22,+0.16),
the peak energy Ep = 126(-5,+6) keV
(chi2 = 72/77 dof).
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.