Emission lines from X-ray-heated accretion disks in low-mass X-ray binaries
Emission lines from X-ray-heated accretion disks in low-mass X-ray binaries
复制标题
低质量 X 射线双星中 X 射线加热吸积盘的发射线
DOI：
10.1086/174485
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
T. Kallman
中科院分区：
文献类型：
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作者：
Y. Ko;T. Kallman
我们研究了双星系统中中心致密天体的X射线照射下吸积盘的结构。X射线可以使盘的上层大气光电离，并形成吸积盘日冕(ADC)，在那里可以形成发射线。我们建立了一个模型来计算ADC的垂直结构和发射光谱，模型中的参数适合于低质量X射线双星。这些模型是由离子和能级布居的非局域热力学平衡计算得到的，包含了10个宇宙丰度元素的大量原子过程。辐射传输用逃逸概率公式来处理。ADC的垂直温度分布由一个康普顿加热区和一个温度约为10(Exp 6)K的中温区组成。在盘状光球附近发生热不稳定性，导致ADC的温度从10(Ep 6)K骤降到10(Ep 4)K的几倍。讨论了ADC在光学、紫外、极紫外和X射线范围内的发射光谱，并与观测结果进行了比较。
We investigate the structure of accretion disks illuminated by X-rays from a central compact object in a binary system. X-rays can photoionize the upper atmosphere of the disk and form an accretion disk corona (ADC) where emission lines can form. We construct a model to calculate the vertical structure and the emission spectrum of the ADC with parameters appropriate to low-mass X-ray binaries. These models are made by nonlocal thermodynamic equilibrium calculations of ion and level populations and include a large number of atomic processes for 10 cosmically abundant elements. Transfer of radiation is treated by using the escape probability formalism. The vertical temperature profile of the ADC consists of a Compton-heated region and a mid-T zone where the temperature is approximately 10(exp 6) K. A thermal instability occurs close to the disk photosphere and causes the temperature of the ADC to drop abruptly from 10(exp 6) K to several times 10(exp 4) K. The emission spectrum in the optical, ultraviolet, extreme ultraviolet, and X-ray range is discussed and compared with the observations.