Abstract

We present the results of the analysis of the SRG/ART-XC observation of the Supergiant Fast X-ray Transient IGR J16195-4545 performed on March 3, 2021. Six bright flares are present in the light curve, with no significant change in hardness occuring during these flares. The spectrum is described with an absorbed power law model with a high energy exponential cutoff showing heavy absorption, with \(N_{\textrm{H}}=(12\pm 2)\times 10^{22}\text{ cm}^{-2}\) and \(\Gamma=0.56\pm 0.15\), \(E_{\textrm{cut}}=13\pm 2\) keV. Adopting the Bayesian block decomposition of the light curve, we measured the properties of the observed flares (duration, rise time, waiting time, released energy and pre-flare luminosity), which are consistent with the quasi-spherical subsonic accretion model. The stellar wind velocity of the supergiant is estimated to be \(v_{w}\approx 500\) km s\({}^{-1}\). Additionally, the system was found to have an unusual near-IR variability.

中文翻译：

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使用 SRG/ART-XC 对超巨快速 X 射线瞬变 IGR J16195–4945 进行光谱和时间分析

摘要

我们展示了 2021 年 3 月 3 日对超巨快速 X 射线瞬变 IGR J16195-4545 进行的 SRG/ART-XC 观测的分析结果。光变曲线中出现了 6 个明亮的耀斑，硬度没有显着变化发生在这些耀斑期间。光谱用吸收幂律模型描述，具有高能量指数截止，显示重吸收，其中\(N_{\textrm{H}}=(12\pm 2)\times 10^{22}\text{ cm} ^{-2}\)和\(\Gamma=0.56\pm 0.15\) , \(E_{\textrm{cut}}=13\pm 2\)keV。采用贝叶斯分块分解光变曲线，测量了观测到的耀斑的特性（持续时间、上升时间、等待时间、释放能量和耀斑前光度），这些特性与准球形亚音速吸积模型一致。超巨星的恒星风速度估计为\(v_{w}\approx 500\) km s \({}^{-1}\)。此外，我们还发现该系统具有不寻常的近红外变异性。