KMS of Xinjiang Astronomical Observatory, CAS
| 南山12 年脉冲星测时观测数据分析与研究 | |
| Alternative Title | Results of 12 yr of Pulsar Timing at Nanshan |
党世军
| |
| Subtype | 博士 |
| Thesis Advisor | 王娜 ; 袁建平 |
| 2020 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Name | 理学博士 |
| Degree Discipline | 天体物理 |
| Keyword | 中子星,脉冲星,脉冲星计时,自行,跃变 |
| Abstract | 脉冲星是天空中最稳定的转子，因为脉冲星的自转能不断地转换为源源不断地向外辐射的高能粒子和电磁辐射, 所以脉冲星的自转频率是逐渐减慢的。我们可以对脉冲星进行长时间的计时观测来得到它的自转参数、位置以及自行。许多脉冲星的自转减慢都受到了计时噪声和周期跃变的影响，而这两者都被认为是受脉冲星内部超流活动所驱使的，因此可以利用它们来研究脉冲星的内部物理。除此之外，脉冲星计时还被用于测试广义相对论、探测引力波以及星际导航等等。在本论文第一个工作中，我们处理分析了南山25米射电望远镜从2002年7月到2014年3月之间87颗脉冲星的计时观测数据。使用Cholesky分析方法，我们确定了48颗脉冲星的位置和自行，其中有24 颗脉冲星的位置与前人文献的结果相对比我们的精度更高，有9颗脉冲星我们是首次得到了它们的自行，13颗脉冲星的自行比前人文献的结果精度更高。我们同时也得到了这87 颗脉冲星的自转参数，其中36 颗脉冲星的自转参数比前人文献给出的结果有所提升。我们在三颗脉冲星PSRs J1722−3632, J1852−0635和J1957+2831上探测到了周期跃变，前面两颗脉冲星我们是首次探测到跃变，更值得一提的是它们的跃变都比较大，其大小\Delta\nu_g/\nu>10-6。PSR J1722−3632是第二老的脉冲星发生大跃变的脉冲星。我们还发现，对于中间年龄(\tau_{c} < 105年) 的脉冲星，我们计算的得到的制动指数的绝对值|?|和特征年龄\tau_{c}具有很强的相关性，并且它们的?的值为正数和负数的数目是几乎相等的。对于年轻脉冲星(\tau_{c}<105年)，|?|和\tau_{c}之间没有相关性，并且?几乎都是正数。在本论文第二个工作中，我们分析了南山25米射电望远镜和Parkes 64米射电望远镜大约13年的计时数据，发现PSR J0742−2822 的自转减慢率的平均值<\dot\nu>在我们的数据段中发生了四次状态改变。我们研究了\dot\nu和 ?50 之间的相关性，发现相关性是不断改变的。此外，并不是所有的<\dot\nu>状态以及相关性的改变都和周期跃变现象有关。我们使用Fermi-LAT Pass 8 (P8R3)的数据得到了这颗脉冲星从2008年8月5号到2019年10月1号总共约11年的能量范围为0.1-300GeV的?射线辐射流量以及不同<\dot\nu>状态时的脉冲轮廓。我们没有发现?射线辐射流量和轮廓在不同的<\dot\nu>状态时有明显的变化。我们的结果说明辐射与自转减慢率以及周期跃变之间的关系在PSR J0742−2822上是要比前人报道的结果更加复杂的。 |
| Other Abstract | Pulsars are the most stable rotators in the universe. They slow down gradually because the rotational energy convert into highly energetic particles and electromagnetic radiations. We observe the pulsars for a long period to obtain its rotational parameters, position and proper motion. However, for many pulsars, their slow down usually disturbed by glitches and timing noise, both of which are considered to be driven by interior superfluid activities the pulsars. Therefore, glitch and timing noise are probes for the internal physics of pulsars. In addition, pulsar timing is also used to test general relativity, detect gravitational waves, and interstellar navigation.In the first work of this thesis, we processed the timing data of 87 pulsars observed by the Nanshan 25-m radio telescope, operated by Xinjiang Astronomical Observatory, from July 2002 to March 2014. Using the Cholesky timing analysis method we have determined positions and proper motions for 48 pulsars, 24 of which are improved positions compared to previously published values. We also present the first published proper motions for nine pulsars and improved proper motions for 13 pulsars. The pulsar rotation parameters are derived and are more accurate than previously published values for 36 pulsars. Glitches are detected in three pulsars: PSRs J1722−3632, J1852−0635 and J1957+2831. For the first two, the glitches are large, with \Delta\nu_{g}/\nu >10-6 , and they are the first detected glitches in these pulsars. PSR J1722−3632 is the second oldest pulsar with large glitch. For the middle-age pulsars (\tau_{c} > 105yr), the calculated braking indices, |?|, are strongly correlated with \tau_{c}and the numbers of positive and negative values of ? are almost equal. For young pulsars (\tau_{c} < 105yr), there is no correlation between |?| and \tau_{c} and most have ? > 0.In the second work of this thesis, we analyzed 13 years of timing data obtained from the Nanshan 25-m radio telescope and the Parkes 64-m radio telescope and found that the average values of the spin-down rate (<\dot\nu>) of PSR J0742−2822 changed in four different states. We investigated the correlation between \dot\nu and W50, and found that the correlation has changed in different <\dot\nu> states. Moreover, not all the changes of <\dot\nu> states and correlation can be associated with the glitch activities. We obtained the long term evolution of ?-ray flux (0.1-300GeV) and the pulse profiles corresponding to the four different states using Fermi-LAT Pass 8 (P8R3) data from 2008 August 5 to 2019 October 1. We did not detected significant change in ?-ray flux and pulse profile. Our results suggest that the connection between pulsar rotation and emission is more complex than previously reported for this pulsar. |
| Pages | 114 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xao.ac.cn/handle/45760611-7/4143 |
| 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 | 党世军. 南山12 年脉冲星测时观测数据分析与研究[D]. 北京. 中国科学院大学,2020. |
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| File Name/Size | DocType | Version | Access | License | ||
| 党世军.pdf（13851KB） | 学位论文 | 暂不开放 | CC BY-NC-SA | Application Full Text | ||
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