GCN Circular 36677
Subject
Konus-Wind detection of GRB 240615A (short/hard)
Date
2024-06-16T16:36:40Z (5 months ago)
From
Dmitry Frederiks at Ioffe Institute <fred@mail.ioffe.ru>
Via
legacy email
D. Frederiks, A.Lysenko, A. Ridnaia, D. Svinkin,
A. Tsvetkova, M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:
The short GRB 240615A (The Fermi GBM team, GCN 36671;
Swift/BAT-GUANO arcminute localization: DeLaunay et al., GCN 36672).
triggered Konus-Wind (KW) at T0=64306.225 s UT (17:51:46.225).
The burst light curve shows a single pulse,
which starts at ~T0-0.02 s and has a duration of ~0.1 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/GRB240615_T64306/
As observed by Konus-Wind, the burst had the total fluence
of 1.85(-0.49,+0.65)x10^-6 erg/cm^2 and a 16-ms peak energy flux,
measured from T0, of 3.21(-0.89,+1.15)x10^-5 erg/cm^2/s
(both in the 20 keV - 10 MeV energy range).
The time-integrated spectrum of the burst (measured from T0 to T0+0.128 s)
is best fit in the 20 keV - 15 MeV range by a power law with exponential
cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.55(-0.27,+0.37) and Ep = 878(-281,+441) keV (chi2 = 24.4/28 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -2.15 (chi2 = 24.5/27 dof).
All the quoted errors are estimated at the 68% confidence level.
All the presented results are preliminary.