论文标题
Maxi J1820+070在2018年爆发中具有多误解观测值的积聚场景
Accretion Scenario of MAXI J1820+070 during 2018 Outbursts with Multi-mission Observations
论文作者
论文摘要
我们使用Swift/XRT，Nicer，Nustar和Astrosat观测值，对黑洞X射线瞬态Maxi J1820+070进行了全面的光谱和时间研究。 Swift/XRT和更好的频谱研究表明，光曲线的平稳性具有光谱软化（硬度从$ \ sim $ 2.5 $ $ 2.5 $变为$ 2 $），随后在第一次爆发时逐渐下降而没有光谱软化。同样，光谱建模表明，第一次爆发处于整个磁盘的低/硬状态，而在第二次爆发期间，热盘发射占主导地位。在整个爆发过程中，由于存在动态发展的电晕，在同时宽带（NICER-NUSTAR，XRT-NUSTAR，ASTROSAT，ASTROSAT数据）中观察到强烈反思签名（反射分数在$ \ sim $ $ $ 0.38-3.8 $之间变化。更好的时序分析显示了准周期振荡（QPO）特征，并且在第一爆发期间的时间频率（下降）阶段的特征频率增加（降低）。我们了解到，由于光谱软化和与局部动力学时间尺度的共振振荡，电晕中电子冷却时间尺度的减少可以解释爆发期间源的上述行为。另外，我们提出了爆发触发的可能方案和源的相关积聚几何形状。
We present a comprehensive spectral and temporal study of the black hole X-ray transient MAXI J1820+070 during its outbursts in 2018 using Swift/XRT, NICER, NuSTAR and AstroSat observations. The Swift/XRT and NICER spectral study shows a plateau in the light curve with spectral softening (hardness changes from $\sim$ $2.5$ to $2$) followed by a gradual decline without spectral softening during the first outburst. Also, spectral modelling suggests that the first outburst is in the low/hard state throughout with a truncated disk whereas the thermal disk emission dominates during the second outburst. During the entire outburst, strong reflection signature (reflection fraction varies between $\sim$ $0.38 - 3.8$) is observed in the simultaneous wideband (NICER-NuSTAR, XRT-NuSTAR, AstroSat) data due to the presence of a dynamically evolving corona. The NICER timing analysis shows Quasi-periodic Oscillation (QPO) signatures and the characteristic frequency increases (decreases) in the plateau (decline) phase with time during the first outburst. We understand that the reduction of the electron cooling timescale in the corona due to spectral softening and the resonance oscillation with the local dynamical timescale may explain the above behavior of the source during the outburst. Also, we propose a possible scenario of outburst triggering and the associated accretion geometry of the source.
