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GCN Circular 26242

Subject
Konus-Wind observation of the recent SGR 1935+2154 activity
Date
2019-11-13T14:22:57Z (4 years ago)
From
Anna Kozlova at Ioffe Institute <ann_kozlova@mail.ioffe.ru>
A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

Since the renewal of bursting activity of the SGR 1935+2154
on October 4 (Wood & Bissaldi et al., GCN 25975,
Ambrosi et al., GCN 26153, GCN 26169, GCN 26171;
Burgess et al., GCN 26160; Ukwatta et al., GCN 26162;
von Kienlin, GCN 26163) Konus-Wind have triggered on
two bursts from this source.

The following is a list of the Konus-Wind triggers with preliminary
estimates of the burst fluences and peak fluxes.
------------------------------------------------------------------
  Date         T0(KW) s UT                  Fl*           PF**
------------------------------------------------------------------
20191104 38666.612 s UT(10:44:26.612)  1.33 +/-0.07  17.0 +/-1.6
20191105 22268.832 s UT(06:11:08.832)  4.85 +/-0.15  29.4 +/-1.9
------------------------------------------------------------------
*  -  Fluence (20-200 keV) in units of 1e-6 erg/cm2

** - Peak Flux (20-200 keV) on 16-ms time scale
        in units of 1e-6 erg/cm2/s

The time-averaged spectra of the bursts are well fit in the
20 - 200 keV range by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with the following parameters:
-------------------------------------------------------------
#   Tbeg-Tend         alpha            Ep(keV)    chi2/dof
-------------------------------------------------------------
1   0 - 0.128    0.47(-0.81,+0.91)    35(-4,+3)     6/13
2   0 - 0.192   -0.29(-0.34,+0.36)    42(-2,+2)     25/19
-------------------------------------------------------------
In terms of spectral parameters and peak fluxes these bursts are
very similar to the intermediate flare from SGR 1935+2154 (Kozlova et 
al.,
MNRAS 460 2, 2016) and, assuming also their durations and fluences,
are typical of short bursts detected by KW during the previous 
activation
of the source.

The Konus-Wind light curves of the bursts are available at
http://www.ioffe.ru/LEA/SGRs/191104_T38666/
http://www.ioffe.ru/LEA/SGRs/191105_T22268/

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