GCN Circular 27715
Subject
Konus-Wind observation of SGR 1935+2154 activity on 2020 May 10
Date
2020-05-11T17:11:42Z (4 years ago)
From
Anna Ridnaia at Ioffe Institute <ridnaia@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:
Two bright, short bursts from SGR 1935+2154
(IPN triangulation: Hurley et al., GCN Circ. 27714)
triggered Konus-Wind at 22322.624 s UT (06:12:02.624)
and 78677.28 s UT (21:51:17.280) on 2020 May 10.
The first burst light curve shows a single, very bright pulse
started with a sharp rise and then smoothly decayed
to the background level. The second burst light curve shows two
pulses separated by a ~0.15 s gap.
Both bursts have a total duration of ~0.4 s.
The emission is seen up to ~500 keV.
As measured by KW, the burst fluences and peak fluxes are as follows:
------------------------------------------------------------------
# Date T0(KW) s UT Fl* PF**
------------------------------------------------------------------
1 20200510 22322.624 s UT(06:12:02.624) 8.70 +/-0.22 38.9 +/-2.0
2 20200510 78677.280 s UT(21:51:17.280) 2.44 +/-0.10 17.8 +/-1.5
------------------------------------------------------------------
* - 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
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 - 0.256 0.08(-0.23,+0.24) 47(-2,+2) 56/25
2 0 - 0.256 0.49(-0.65,+0.71) 37(-3,+2) 39/24
-------------------------------------------------------------
The Konus-Wind light curves of the bursts are available at
http://www.ioffe.ru/LEA/SGRs/200510_T22322/
http://www.ioffe.ru/LEA/SGRs/200510_T78677/
All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.