GCN Circular 44894
Subject
Konus-Wind detection of GRB 260601A
Event
Date
2026-06-10T13:16:20Z (4 months ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
Via
Web form
A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short-duration GRB 260601A
(Fermi-GBM detection: Fermi GBM team, GCN 44755,
Holzmann Airasca et al., GCN 44760;
Glowbug detection: Cheung et al., GCN 44763;
GECAM-B detection: Wang et al., GCN 44778;
SVOM-GRM detection: Wang et al., GCN 44793;
CALET-GBM detection: Yamaoka et al., GCN 44817;
IPN triangulation: Svinkin et al., GCN 44893)
triggered Konus-Wind at T0=39609.166 s UT (11:00:09.166).
The burst light curve shows a multipeaked structure
which starts at ~T0 and has a total duration of ~0.2 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/GRB260601_T39609/
As observed by Konus-Wind, the burst
had the total fluence of 3.05(-0.27,+0.29)x10^-6 erg/cm2,
and the 16-ms peak flux, measured from T0+0.078 s,
of 4.04(-0.53,+0.55)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+0.192 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 = -0.44(-0.13,+0.14)
and Ep = 780(-91,+107) keV (chi2 = 36/39 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 = 36/38 dof).
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.