It has long been speculated that the nature of the hard X-ray corona may be an important second driver of black hole state transitions, in addition to the mass accretion rate through the disk. However, a clear physical picture of coronal changes has not yet emerged. We present results from a systematic analysis of Rossi X-ray Timing Explorer observations of the stellar mass black hole binary XTE J1650-500. All spectra with significant hard X-ray detections were fit using a self-consistent, relativistically-blurred disk reflection model suited to high ionization regimes. Importantly, we find evidence that both the spectral and timing properties of black hole states may be partially driven by the height of the X-ray corona above the disk, and related changes in how gravitational light bending affects the corona--disk interaction. Specifically, the evolution of the power-law, thermal disk, and relativistically--convolved reflection components in our spectral analysis indicate that: (1) the disk inner radius remains constant at \rin$=1.65\pm0.08 GM/c^2$ (consistent with values found for the ISCO of XTE J1650-500 in other works) throughout the transition from the \textit{brighter} phases of the low-hard state to the intermediate states (both the hard-intermediate and soft-intermediate), through to the soft state and back; (2) the ratio between the observed reflected X-ray flux and power-law continuum (the "reflection fraction", R) increases sharply at the transition between the hard-intermediate and soft-intermediate states ("ballistic" jets are sometimes launched at this transition); (3) both the frequency and coherence of the high-frequency quasi-periodic oscillations (QPOs) observed in XTE J1650-500 increase with R. We discuss our results in terms of black hole states and the nature of black hole accretion flows across the mass scale.
On the light-bending model of X-ray variability of MCG-6-30-15
我们应用光弯曲模型的X射线可变性的朱雀数据的塞弗特1星系MCG-6-30-15。我们分析了能量的均方根（rms）的变异性的依赖性，并讨论了必要的条件，该模型来解释的源变异性约5-8千电子伏的特征减少。一个模型，其中的X射线源径向移动，而不是垂直接近磁盘表面，确实可以重现减少的变化附近的Fe K α线的能量，虽然正式的拟合质量差。然后，该模型预测的能量谱，这可以与观测数据进行比较。光谱是强烈的反射为主，并没有提供一个很好的适合朱雀光谱数据的来源。这一结果与以前的一些说法的不一致可以追溯到我们使用的数据在一个更宽的能带，在光谱中的热吸收体的影响不能忽略。
The Very Bright and Nearby GRB 130427A: The Extra Hard Spectral Component and Implications for Very High-energy Gamma-ray Observations of Gamma-ray Bursts
