GCN Circular 40631
Subject
Konus-Wind detection of GRB 250601A
Date
2025-06-05T15:52:19Z (a day 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 250601A
(Fermi GBM detection: Fermi GBM team, GCN 40596; Sharma et al., GCN 40621;
Swift/BAT-GUANO localization: DeLaunay et al., GCN 40600)
triggered Konus-Wind at T0=62975.326 s UT (17:29:35.326).
The burst light curve shows a multi-peaked pulse,
which starts at ~T0-0.5 s and has a total duration of ~0.8 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/GRB250601_T62975/
As observed by Konus-Wind, the burst
had a fluence of 2.02(-0.28,+0.31)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.004 s,
of 7.00(-2.01,+2.06)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).
Since the brightest peak of the burst light curve
was detected before the trigger, the spectral analysis
was performed using the KW 3-channel light curve data.
Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.492 s to T0+0.276 s)
by a power law with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = 0.31(-0.37,+0.52) and Ep = 436(-62,+76) keV.
All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.