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Further Konus-Wind observations of Galactic transient GRS 1915+105 in outburst

ATel #13316; A. Ridnaia, S. Golenetskii, R. Aptekar, D. Frederiks, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko (Ioffe Institute), and T. Cline
on 27 Nov 2019; 12:21 UT
Credential Certification: Anna Kozlova (ann_kozlova@mail.ioffe.ru)

Subjects: X-ray, Black Hole, Transient

On November 20, 2019 Konus-Wind (KW) detected, within the time interval of ~2 hours, three hard X-ray bursts with durations of several hundreds of seconds. Taking into account that one of these bursts was observed by NICER (Atel #13308) and is due to GRS 1915+105; and consistency of the KW ecliptic latitude response with the position of GRS 1915+105, we suggest that the flaring activity observed by KW is due to GRS 1915+105. There are one more possible weak/soft episode of the source activity at 02:12.

The following is a list of the Konus-Wind detected episodes with preliminary estimates of the burst fluences.

 
Date        Tstart(UT)  Tstart(MJD)  Duration(s) Fluence (20-1000 keV; 1e-5 erg/cm2) 
2019-11-20  04:47       58806.699    ~383        1.6 +/- 0.1 
2019-11-20  05:37       58806.734    ~836        1.3 +/- 0.2  
2019-11-20  06:23       58806.766    ~589        1.1 +/- 0.2 
The KW light curves of the flares and power-law index evolution during the observed light curve (the PL index errors are 68% CL) are provided at the link below.

Further KW observations of the activity of the source will be reported. All the presented results are preliminary.

Konus-Wind is a gamma-ray spectrometer operating onboard the NASA GGS-WIND spacecraft since November 1994. It contains two NaI scintillation detectors continuously observing the whole sky and covers the energy band from ~20 keV to ~15 MeV.

GRS 1915+105 Konus-Wind waiting mode lightcurve