具有PHOENIX的X射线新星的大质量NLTE模型
Massive NLTE models for X-ray novae with PHOENIX
摘要：
X射线光栅光谱证实了在爆发的超软源（SSS）阶段，新星的质量继续损失。在这项工作中，扩大新星大气模型的发展和使用的SSS光谱上的质量损失的影响进行了研究。非常高的温度加上高膨胀速度和大的径向延伸使得SSS相的新星非常有趣，但也很难建模。PHOENIX辐射输运程序曾用于SSS新星的计算，但在对原有计算结果的分析中发现了一些问题，从而提出了新的计算方法和改进程序：1）改进NLTE模块（2）一种新的流体静力学-动力学混合新星大气装置; 3）在纯NLTE中处理模型（对于任何不透明度没有LTE近似）。使用新的框架，计算了适量的模型（受计算时间限制）。这些显示：1）各种大气条件下的系统行为，2）扩展对模式光谱的影响很大，3）光谱对大气结构的细节很敏感。这些模型与目前可用的10个曝光良好的光栅光谱进行了比较：5x V4743 Sgr，3x RS Oph和2x V2491 Cyg。尽管模型是在一个粗糙的网格上，但它们与观测结果的匹配程度令人惊讶。此外，流体静力学模型计算。复制的数据显然是劣于扩大模型，更重要的是，他们的解释与流体静力学模型导致相反的结论，从扩大模型。该模型使推导出准确的约束条件的物理条件深在新星大气中，揭示只有在SSS阶段。
英文摘要：
X-ray grating spectra provide the confirmation of continued mass loss from novae in the super-soft source (SSS) phase of the outburst. In this work expanding nova atmosphere models are developed and used to study the effect of mass loss on the SSS spectra. The very high temperatures combined with high expansion velocities and large radial extension make nova in the SSS phase very interesting but also difficult objects to model. The radiation transport code PHOENIX was applied to SSS novae before, but careful analysis of the old results has revealed a number of problems which lead to new methods and improvements to the code: 1) an improved NLTE module (a new opacity formalism, rate matrix solver, global iteration scheme, and temperature correction method); 2) a new hybrid hydrostatic-dynamic nova atmosphere setup; 3) the models are treated in pure NLTE (no LTE approximation for any opacity). With the new framework a modest amount of models (limited by computation time) are calculated. These show: 1) systematic behaviour for various atmospheric conditions, 2) the effect of expansion on the model spectrum is significant, and 3) the spectra are sensitive to the details of the atmospheric structure. The models are compared to the ten well-exposed grating spectra presently available: 5x V4743 Sgr, 3x RS Oph, and 2x V2491 Cyg. Although the models are on a coarse grid they do match the observations surprisingly well. Also, hydrostatic models are computed. The reproduction of the data is clearly inferior to the expanding models and, more importantly, their interpretation with hydrostatic models leads to conclusions opposite to those from expanding models. The models enable the derivation of accurate constraints on the physical conditions deep in the nova atmosphere that are revealed only in the SSS phase.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
