论文标题
Swift/BAT和RXTE/ASM观察35天的X射线周期X-1
Swift/BAT and RXTE/ASM Observations of the 35-day X-ray Cycle of Hercules X-1
论文作者
论文摘要
Swift/BAT和RXTE/ASM观察结果已经监视了X射线二进制系统的X-1，每个X-1大约14。5年，并且两者都在监视她的X-1期限约5.5年。在这里，我们使用这些观察结果研究了35天的周期。使用互相关方法，我们找到了〜150个周期的峰峰时，Swift/BAT观察到了〜150个周期，RXTE/ASM观察到了〜150个周期。这些周期包括两种仪器都观察到的约60个。 RXTE/ASM测量值的噪声水平大于Swift/BAT的噪声水平，导致高峰时段的不确定性较大。 35天循环长度的分布可以与平均34.79 d和$σ$ 1.1 d的高斯人拟合。 35天周期峰的轨道相的分布非常适合均匀分布，其中76％的周期，加上高斯分布在轨道相位〜0.5，其中24％的周期。我们在Swift/BAT的15-50 KEV频段中以及RXTE/ASM的2-12 KEV频段中构建了长期的35天灯泡。高能带显示在短状态下的变化更大，低能带显示主要高状态的变化更大。这与预进积盘模型是35天周期的原因一致。
Swift/BAT and RXTE/ASM observations have monitored the X-ray binary system Her X-1 for approximately 14.5 years each, and both were monitoring Her X-1 for a period of ~5.5 years. Here we study the 35-day cycle using these observations. Using a cross-correlation method we find the times of peaks of the 35-day cycles for ~150 cycles observed by Swift/BAT and ~150 cycles observed by RXTE/ASM. These cycles include ~60 observed with both instruments. The noise level of the RXTE/ASM measurements is larger than that of Swift/BAT, resulting in larger uncertainty in peak times. The distribution of 35-day cycle lengths can be fit with a Gaussian with mean 34.79 d and $σ$ of 1.1 d. The distribution of orbital phases of 35-day cycle peaks is well fit by a uniform distribution, with 76 percent of the cycles, plus a Gaussian distribution peaked at orbital phase ~0.5, with 24 percent of the cycles. We construct the long-term average 35-day lightcurve in the 15-50 keV band from Swift/BAT, and in the 2-12 keV band from RXTE/ASM. The high energy band shows more variability in the Short High state and the low energy band shows more variability in the Main High state. This is consistent with a precessing accretion disk model as cause of the 35-day cycle.
