论文标题
V404 Cygni在2015年爆发期间的积聚流动动力学研究
Study of Accretion Flow Dynamics of V404 Cygni during its 2015 Outburst
论文作者
论文摘要
V404 Cygni的2015年爆发是一种不寻常的爆发，具有几种X射线和无线电耀斑以及光谱和时机特性的快速变化。爆发发生在$ 26美元的黑洞不活动之后。我们使用{\ it swift}/xrt和{\ it swift}/bat数据在$ 0.5-150 $ keV的能量范围内研究源在爆发的初始阶段的积聚流属性。我们已经使用两个组件的对流流（TCAF）模型进行了光谱分析。提取了几种流程参数，例如两种类型的吸积率（Keplerian磁盘和亚算筒），冲击参数（位置和压缩比），以了解积聚流动动力学。我们计算了爆发的电气磁场$ b $，发现最高的$ b \ sim 900 $〜高斯。功率密度光谱（PDS）没有断裂，这表明开普勒磁盘成分没有或更少的贡献，从光谱分析的结果也可以看出。在PDS中未观察到明显的准周期振荡（QPO）的特征。这是由于冷却时间尺度和后震后事物的插入时间尺度的不匹配。
The 2015 Outburst of V404 Cygni is an unusual one with several X-ray and radio flares and rapid variation in the spectral and timing properties. The outburst occurred after $26$ years of inactivity of the black hole. We study the accretion flow properties of the source during its initial phase of the outburst using {\it Swift}/XRT and {\it Swift}/BAT data in the energy range of $0.5-150$ keV. We have done spectral analysis with the two-component advective flow (TCAF) model fits file. Several flow parameters such as two types of accretion rates (Keplerian disk and sub-Keplerian halo), shock parameters (location and compression ratio) are extracted to understand the accretion flow dynamics. We calculated equipartition magnetic field $B$ for the outburst and found that the highest $B \sim 900$~Gauss. Power density spectra (PDS) showed no break, which indicates no or very less contribution of the Keplerian disk component, which is also seen from the result of the spectral analysis. No signature of prominent quasi-periodic oscillations (QPOs) is observed in the PDS. This is due to the mismatch of the cooling timescale and infall timescale of the post-shock matter.
