KMS of Xinjiang Astronomical Observatory, CAS
| 吸积毫秒脉冲星中X射线暴研究 | |
| Alternative Title | The research about X-ray burst from accreting millisecond pulsar |
吴子为
| |
| Subtype | 硕士 |
| Thesis Advisor | 丁国强 |
| 2018-06 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Name | 理学硕士 |
| Degree Discipline | 天体物理 |
| Keyword | X射线暴 吸积流 SAXJ1748.9-2021 |
| Abstract | X射线暴在中子星双星系统中很常见的现象，包括I型x射线暴，Ⅱ型X射线暴和不规则X射线暴。来自伴星的吸积物质在中子星表面堆积，不断被压缩和加热，当中子星表面温度足够高时，吸积物质发生核聚变，也就是我们所说的I型X射线暴。我们对Ⅱ型X射线暴和不规则X射线暴了解很少。对I型x射线暴的进一步研究能够很好地帮助我们了解中子星双星系统：包括用暴频限制中子星自转参数、对冕区的制冷、对吸积流的影响、限制中子星的质量和半径。 利用RXTE卫星的数据，对吸积毫秒脉冲星SAXJ1748.9-2021在2010年爆发中观测到的X射线暴做了详细研究。最终发现了13个X射线暴，包括12个I型X射线暴和1个不规则X射线暴，在考虑了各向异性辐射之后，这些X射线暴发生在源吸积率为（1-5）%爱丁顿吸积率下。通过用一个包含可变吸积流的复合模型：phabs*（bbodyrad+fa*（phabs*（bbody+powerlaw+Gaussian））），来拟合X射线暴的能谱。对于某些X射线暴，当爆发光度很大时，随着爆发光度的增加，吸积流的吸积率会减小。另外，根据这些X射线暴的性质，这些X射线暴发生在富氦或纯氦环境下。不规则x射线暴的能谱能够被黑体谱很好地拟合。进一步分析发现，不规则X射线暴的爆发深度比其它I型X射线暴的爆发深度要小得多。所以，我们认为这个不规则x射线暴起源于较浅区域的热核反应。 |
| Other Abstract | X-ray burst is commonly seen in neutron star(NS) X-ray binary, including type-I X-ray burst, type-II X-ray burst and irregular X-ray burst. As accreted hydrogen/helium matter accumulates on the surface of the NS, the accreted matter from the companion star is compressed and heated. occasionally leading to unstable burning if the temperature is sufficiently high. These bursts are known as type-I X-ray bursts. We barely knew about type-II X-ray bursts and irregular X-ray bursts. The research of type-IX-ray bursts will help us understand NS X-ray binary: measuring the stellar spin using burst Oscillation、 the cooling to corona、 the influence to the persistent emission and measuring the stellar mass and Radius. We present a detailed study of X-ray bursts during the 2010 outburst of the accreting millisecond X-ray pulsar SAXJ1748.9-2021 observed with the Rossi X-ray Timing Explorer. We find 13 X-ray bursts including 12 standard type-I X-ray bursts and oneirregular X-ray burst lacking a cooling tail, occurring at x(1-5)% imedd persistent emission after considering anisotropic X-ray emission. By fitting the burst spectrumwith a combination of adjustable persistent emission models,i.e., phabs*(bbodyrad+fa*(phabs*(bbody+powerlaw+Gaussian), we find that for some X-ray bursts during luminous phase, the multiplicative factor fa decreases with the increase in burst flux. According to the type-IX-ray burst characteristics, we infer that these type-I X-ray bursts originate from helium-rich or pure-helium environments. The spectra of the irregular X-ray burst can be fitted well by a blackbody model. We also derive its ignition depth, which is obviously smaller than those of type-I X-ray bursts in this source. Thus, we suggest that this irregular X-ray burst originates from thermonuclear flash in a shallow ocean. |
| Pages | 52 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/2478 |
| Collection | 研究生学位论文 |
| Affiliation | 中国科学院新疆天文台 |
| First Author Affilication | Xinjiang Astronomical Observatory, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | 吴子为. 吸积毫秒脉冲星中X射线暴研究[D]. 北京. 中国科学院大学,2018. |
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| 学位论文-吴子为.pdf（7279KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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