标题： 利用Swift/BAT连续监测Her X-1的脉冲周期变化 显示英文标题

标题： Continuous monitoring of pulse period variations in Her X-1 using Swift/BAT

摘要： 背景：监测吸积双星脉冲星的脉冲周期变化是研究中子星磁层与吸积盘相互作用的重要工具。 虽然最亮的X射线脉冲星的X射线流量已成功监测多年（例如，使用 RXTE/ASM、CGRO/BATSE、Swift/BAT），但连续监测它们的脉冲时间特性至今仍非常有限。 目标：在我们的工作中，我们展示了Swift/BAT观测可用于监测明亮X射线源的相干脉冲，并利用Swift存档数据研究最神秘的X射线脉冲星之一，赫拉克勒斯 X-1。 这里对Her X-1的X射线脉冲星的脉冲周期和脉冲周期导数进行了长达几年的准连续监测（<~4年）。 我们将观测结果与吸积理论预测进行比较，并用其测试系统的物理模型的不同方面。 方法：在我们的分析中，我们使用从2005年初（发射后不久）到现在的Swift/BAT积累的数据。 为了搜索脉冲并进行后续分析，我们使用了BAT探测器在整个视场内测量的计数率。 结果：测定了Her X-1中自旋加速率与X射线亮度之间相关性的斜率，发现其与基本吸积转矩理论的预测一致。 结合之前测得的系统轨道周期的长期衰减，讨论了脉冲周期的观测行为，并假设靠近吸积盘内边界物质的喷射现象。 显示英文摘要

摘要： Context: Monitoring of pulse period variations in accreting binary pulsars is an important tool to study the interaction between the magnetosphere of the neutron star and the accretion disk. While the X-ray flux of the brightest X-ray pulsars have been successfully monitored over many years (e.g. with RXTE/ASM, CGRO/BATSE, Swift/BAT), the possibility to monitor their pulse timing properties continuously has so far been very limited. Aims: In our work we show that the Swift/BAT observations can be used to monitor coherent pulsations of bright X-ray sources and use the Swift archival data to study one of the most enigmatic X-ray pulsars, Hercules X-1. A quasi-continuous monitoring of the pulse period and the pulse period derivative of an X-ray pulsar, here Her X-1, is achieved over a long time (<~ 4 yrs). We compare our observational results with predictions of accretion theory and use them to test different aspects of the physical model of the system. Methods: In our analysis we use the data accumulated with Swift/BAT starting from the beginning of 2005 (shortly after launch) until the present time. To search for pulsations and for their subsequent analysis we used the count rate measured by the BAT detector in the entire field of view. Results: The slope of the correlation between the locally determined spin-up rate and the X-ray luminosity is measured for Her X-1 and found to be in agreement with predictions of basic accretion torque theory. The observed behaviour of the pulse period together with the previously measured secular decrease of the system's orbital period is discussed in the frame of a model assuming ejection of matter close to the inner boundary of the accretion disk.