论文标题
X-1中的回旋线能量：衰减后稳定
The cyclotron line energy in Her X-1: stable after the decay
论文作者
论文摘要
我们总结了2012年至2019年间付出的努力的结果，以通过反复的nustar观察结果遵循〜x-1中回旋线的演变。先前观察到的回旋线能量的近20年衰减已在2012年左右结束：从那里开始，脉冲平均通量校正的回旋线线能量一直保持稳定且恒定，ECYC的平均值=（37.44 +/- 0.07）KeV（标准化为6.8 rxte/asm-asm-cts/s）。现在以高精度测量了2007年发现的ECYC的通量依赖性，斜率为（0.675 +/- 0.075）keV/（ASM-CTS/s），对应于ECYC的6.5％的ECYC增加，以增加两倍的频率。我们还发现，所有线参数以及连续参数均显示与X射线通量的相关性。尽管ECYC和X射线通量（正和负）之间的相关性现在以几种对基础物理学有各种建议的吸收二进制物而闻名，但到目前为止，长期衰减的现象仅在她的〜x-1和vela〜x-1中才能看到，而具有令人信服的解释。
We summarize the results of a dedicated effort between 2012 and 2019 to follow the evolution of the cyclotron line in Her~X-1 through repeated NuSTAR observations. The previously observed nearly 20-year long decay of the cyclotron line energy has ended around 2012: from there onward the pulse phase averaged flux corrected cyclotron line energy has remained stable and constant at an average value of Ecyc= (37.44+/-0.07) keV (normalized to a flux level of 6.8 RXTE/ASM-cts/s). The flux dependence of Ecyc discovered in 2007 is now measured with high precision, giving a slope of (0.675+/-0.075) keV/(ASM-cts/s), corresponding to an increase of 6.5% of Ecyc for an increase in flux by a factor of two. We also find that all line parameters as well as the continuum parameters show a correlation with X-ray flux. While a correlation between Ecyc and X-ray flux (both positive and negative) is now known for several accreting binaries with various suggestions for the underlying physics, the phenomenon of a long-term decay has so far only been seen in Her~X-1 and Vela~X-1, with far less convincing explanations.
