银河黑洞X射线双星系统的X射线辐射机制及吸积流结构
文献类型：学位论文
| 作者 | 严丽红 |
| 学位类别 | 博士 |
| 答辩日期 | 2011-05-26 |
| 授予单位 | 中国科学院研究生院（云南天文台） |
| 授予地点 | 北京 |
| 导师 | 王建成 |
| 关键词 | 黑洞X射线双星 辐射机制 吸积盘 RXTE卫星 |
| 其他题名 | The radiation mechanism and and the accretion flow configuration of the X-ray Black-Hole Binaries in Galactic |
| 学位专业 | 天体物理 |
| 中文摘要 | 大部份银河黑洞X射线双星都表明半周期爆发，根据爆发过程中X射线的发射性质识别了不同谱态。爆发通常从低硬态开始，经历中间态或甚高态，进入高软态，然后以具有50%流量下降的磁滞行为重新回到低硬态，最后返回宁静态。X射线发射性质在整个爆发过程中发生大的变化，表明在吸积物理（吸积流结构和X射线辐射机制）中发生的重要变化。 通过对软X射线暂现XTE J1650- 500于2001=2002爆发的RXTE观测数据的分析，我们得到对硬态与软态过程中的康普顿化过程的约束，硬态为热康普顿化过程，软态为体运动康普顿化过程；拟合得到源在从硬态到软态的过渡过程中，康普顿云收缩，有效表面积降低»23倍，建议除了质量吸积率之外，康普顿化等离子体的体积也是驱动态过渡的因素；硬态过程中铁线流与幂律流之间的非线性关系能在光线弯曲模型中进行解释；结合X射线能谱性质，喷流与高频准周期振荡的出现，我们建议源的吸积流结构为（jet+corona+disk）。 目前，对陡幂律态能谱延伸到1MeV能量处的强的非热成份的物理起源仍然不甚了解，还有与陡幂律态过程中相关的高频准周期振荡之间的关联等问题都缺乏整体统一的理解。大部分解释陡幂律态谱的模型引入来自于盘的种光子在一个非热冕中的逆康普顿散射。有关非热电子的起源导致了很多具有复杂几何与回馈机制的模型。还有在黑洞50Rg以内的内流亚开普勒流环境中提出的体运动康普顿化模型。当前的陡幂律态模型很难解释对在X射线光变曲线中观测到的振荡模具有潜在影响的辐射机制。这里，我们给出在X射线双星陡幂律态的X射线发射起源上的新的解释。X射线发射的幂律成份是在黑洞最内稳定圆轨道附近转动的高度磁化致密耀斑中的相对论电子的同步辐射，并且具有由电子加速率决定的延伸到MeV能量处的硬谱。然后这些光子被周围等离子体下散射且形成观测到的陡谱。谱的高能截断能量只由热斑中电子加速率决定。我们讨论模型与高频准周期振荡，与陡幂律态的极端高光度之间的相关性。 |
| 英文摘要 | Most Galactic black-hole binaries show semi-periodic outburst, and be classfied with different X-ray state according to the X-ray properties in the whole outburst. From onset of the outburst, the system can go through low-hard state, intermediate state or very high state, high soft state, then low hard state again (but the luminosity is only a half of the rise phase), and the last quiet state. Dur- ing the whole outburst, their X-ray properties, accretion flow and the mechanism of the X-ray radiation, show large varieties, implying the signi¯cant changes in the accretion physics. We have carried out a detailed analysis of the X-ray transient XTE J1650-500 as observed during its discovery outburst in 2001/2002 by the Rossi X-Ray Timing Explorer. By ¯tting the RXTE observations with phenomenological and physical models reasonably, we got some constrains on the Compton process for the hard state and the soft state, i.e., thermal Comptonization dominating the hard X-ray emission in the hard state and the bulk-motion Comptonization controlling in the soft state. During the state transition from the hard to the soft, a contraction of the Comptonization region (Compton cloud) with the effective surface area decreasing a factor of ~23 suggests that in addition to massaccretion rate there is another parameter responsible for the state transition in XTE J1650-500, and this second driving factor may the the scale of the Comptonizing plasma. And the anticorrelation between the flux of the Fe K-alpha emission line and the power-law flux in hard state can be well explained in the light-bending model. combing the obtained energy spectra properties with us and the prior achievement of radio observation and the timing analysis, we suggest the accretion con¯guration of the accretion flow in XTE J1650-500 is a composite of jet+corona+disk. Until now, the physical origin of the SPL (steep power-law) state generating HFQPOs, extremely high luminosity and spectra that extend to above MeV, remains one of the outstanding problems in Black-hole binaries (BHBs). Most models on the spectra of the SPL state invoke inverse Compton scattering of seed photons from the disk in a nonthermal corona. The origin of the nonthermal electrons has led to the models with complicated geometry and feedback mechanisms. Alternative models involve bulk motion Comptonization in the context of a converging sub-Keplerian flow within 50Rg of the Black Hole. Current models of the SPL state are deffcient in terms of specifying the radiation mechanisms that would imprint a given oscillation mode into the X-ray light curve. Here, we proposed a new scenario of the hard X-ray origin in the SPL state which is based on two standard processes, in which the hard X-ray photons with a power-law spectrum extending to above MeV bands is firstly produced by the synchrotron radiation of magnetized compact spots orbiting near the ISCO and then these photons are down-scattered by the thermal electrons of surrounding corona to form an observed steep spectrum. The high energy cutoff of the spectrum is only determined by the electron acceleration rate in the spot. At last, we discuss the correlations of the HFQPOs (high-frequency-quasi-periodic-oscillation) and the extreme high luminosity of the SPL state to this model. |
| 学科主题 | 天文学 |
| 语种 | 中文 |
| 源URL | [http://ir.ynao.ac.cn/handle/114a53/5086]  |
| 专题 | 云南天文台_高能天体物理研究组 |
| 推荐引用方式 GB/T 7714 | 严丽红. 银河黑洞X射线双星系统的X射线辐射机制及吸积流结构[D]. 北京. 中国科学院研究生院（云南天文台）. 2011. |
入库方式： OAI收割
来源：云南天文台
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