论文标题
B型B型准周期振荡GX 339-4中的双核心构造模型
Dual-Corona Comptonization model for the Type-B Quasi-Periodic Oscillations in GX 339-4
论文作者
论文摘要
表征黑洞低质量X射线二进制（BHXB）的快速变异性可以帮助我们了解这些来源最内向区域的几何和物理性质。尤其是，在爆发的软中间状态（SIMS）期间在BHXB中观察到的B型准准周期振荡（QPO）被认为与相对性射流的弹出相关。 SIMS中源的X射线频谱的特征是具有主导的软黑体状分量 - 与积聚盘相关联 - 与构成区域或Corona相关的硬组件。在2021年爆发期间，尼和阿斯特罗萨特在GX 339 $ -4中观察到了强大的B型QPO。我们发现，QPO的分数RMS频谱保持不变，以$ \ sim $ \ sim $ 1％的能量$ \ sim $ \ sim $ 1.8 keV，然后随着能量增加到$ \ sim $ \ sim $ \ sim $ \ sim $ 17％，$ \ sim $ \ $ 30 $ 30 kev。我们还发现，滞后频谱是“ U形”的，从$ \ sim $ \ sim $ 1.2 rad at 0.7 keV升至0 $ \ sim $ 3.5 keV，并在更高的能量下再次增加到$ \ sim $ \ sim $ 0.6 rad in 20 $-$ $ 30 kev。使用最近开发的时间依赖性的组合模型，我们同时拟合了QPO的分数RMS和滞后光谱，以及GX 339 $ -4的时间平均能量光谱，以限制我们观察到的可变性的区域的物理参数。我们建议，在GX 339 $ -4中观察到的B QPO的辐射特性可以通过两个物理连接的组合区域来解释，它们通过X射线光子的反馈环与积聚盘相互作用。
Characterising the fast variability in black-hole low-mass X-ray binaries (BHXBs) can help us understand the geometrical and physical nature of the innermost regions of these sources. Particularly, type-B quasi-periodic oscillations (QPOs), observed in BHXBs during the soft-intermediate state (SIMS) of an outburst, are believed to be connected to the ejection of a relativistic jet. The X-ray spectrum of a source in the SIMS is characterised by a dominant soft blackbody-like component - associated with the accretion disc - and a hard component - associated with a Comptonizing region or corona. Strong type-B QPOs were observed by NICER and AstroSat in GX 339$-$4 during its 2021 outburst. We find that the fractional rms spectrum of the QPO remains constant at $\sim$1 per cent for energies below $\sim$1.8 keV and then increases with increasing energy up to $\sim$17 per cent at 20$-$30 keV. We also find that the lag spectrum is "U-shaped", decreasing from $\sim$1.2 rad at 0.7 keV to 0 rad at $\sim$3.5 keV, and increasing again at higher energies up to $\sim$0.6 rad at 20$-$30 keV. Using a recently developed time-dependent Comptonization model, we fit simultaneously the fractional rms and lag spectra of the QPO and the time-averaged energy spectrum of GX 339$-$4 to constrain the physical parameters of the region responsible for the variability we observe. We suggest that the radiative properties of the type-B QPOs observed in GX 339$-$4 can be explained by two physically-connected Comptonizing regions that interact with the accretion disc via a feedback loop of X-ray photons.
