GCN Circular 38581
Subject
Konus-Wind detection of GRB 241213A (EP 241213a)
Event
Date
2024-12-16T15:00:39Z (a year 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 long-duration GRB 241213A
(Swift-BAT detection: Gupta et al., GCN 38547;
INTEGRAL-SPI-ACS detection: Barria et al., GCN 38556),
associated with the fast X-ray transient EP241213a
(Zhou et al., GCN 38554; Barria et al., GCN 38556),
triggered Konus-Wind at T0=8344.058 s UT (02:19:04.058).
The burst light curve shows a single pulse,
which starts at ~T0-3.1 s and has a total duration of ~7.6 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/GRB241213_T08344/
As observed by Konus-Wind, the burst
had a fluence of 1.04(-0.07,+0.07)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+1.056 s,
of 4.78(-1.05,+1.06)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+8.448 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 = -0.88(-0.17,+0.18)
and Ep = 236(-24,+30) keV (chi2 = 74/77 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 = 73/76 dof).
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.