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GCN Circular 32792

Subject
Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17
Date
2022-10-18T14:35:09Z (2 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru>
A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

A short, soft, SGR-like burst
triggered Konus-Wind on 2022 October 17 at
T0=40483.010 s UT (11:14:43.010).

The Konus-Wind ecliptic latitude response is consistent
with the SGR 1935+2154 position. So, taking in account
the ongoing bursting activity of this source, burst
time history, and softness of its spectrum (as observed
by Konus-Wind), we suggest that this burst is likely
a SGR flare originated from SGR 1935+2154.

The burst light curve shows a single pulse
started at ~T0-56 ms with a total duration of ~202 ms.
The emission is seen up to ~200 keV.

The Konus-Wind light curve of this burst is available at
http://www.ioffe.ru/LEA/SGRs/221017_T40483/

As observed by Konus-Wind, the burst
had a fluence of 2.16(-0.10,+0.10)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.006 s,
of 2.84(-0.22,+0.22)x10^-5 erg/cm2/s
(both in the 20 - 500 keV energy range).

The spectrum of the burst
(measured from T0 to T0+0.192 s)
is best fit in the 20 - 500 keV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.71(-0.50,+0.57)
and Ep = 33(-7,+5) keV (chi2 = 15/19 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.
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