超新星遗迹与周围环境作用的研究

发布时间：2018-05-20 11:26

本文选题：超新星 + 超新星遗迹(Kes　；参考：《南京大学》2011年博士论文

【摘要】：超新星遗迹是在超新星爆发过程中喷射出的前身星物质与周围星周／星际介质相互作用形成的产物。它将会释放大量能量和金属元素到星际介质中,对星际介质的物理和化学演化产生重要影响。研究超新星遗迹演化的重要一环是研究其与星际介质之间的相互作用。事实上,超新星遗迹中的很多观测现象都起源于其与不均匀的星周/星际介质之间的相互作用。但是超新星遗迹和不均匀星周/星际介质之间的相互作用涉及到许多复杂的物理过程,这使得对其的研究存在很多困难。本文将介绍我在超新星遗迹以及它和周围不均匀星际介质之间相互作用方面的工作。首先,在第一章中对超新星、星际介质、强激波物理、超新星遗迹演化等作了简要回顾；接下来,研究了几个具有代表性的情况：超新星遗迹与分子云的相互作用(在第二章中研究了超新星遗迹Kes 69；在第4.2节中研究了超新星遗迹W49B),超新星遗迹与中等密度云块的相互作用(在第三章中研究了超新星遗迹Cygnus Loop),和有过电离现象的超新星遗迹在具有特别分布的星周/星际介质中的演化(在第4.3节中研究了超新星遗迹W49B)。研究涉及不同情况下的超新星遗迹与云块作用的物理和化学演化。对于超新星遗迹Kes 69,我们确认了其与系统速度在～85kms-1的分子云的关联性,这使得我们得到遗迹的运动学距离为5.2kpc。通过12CO(J=1-0)的观测分别在东南和西北区域发现了分子云圆弧,它们大致分布在一个圆上。这些分子气体很可能是经由前身星星风扫积堆积而成。对于超新星遗迹Cygnus Loop,我们研究了XMM-Newton X射线望远镜对其东面一较亮区域(被称作XA区域)的观测。结果显示,这片区域星际介质密度较大并且有成团性；还发现这里星际介质的C,N,O丰度只有太阳丰度的0.2倍左右。X射线谱可以被两个热成分拟合,分别对应了被震击的云块物质和周围热的冕物质。我们应用了新近发展起来的一个诊断工具对比了谱分析结果和理论预期,确认了热传导在这个区域中的激波与云块相互作用的演化过程中起到主导作用。我们还发现了一个前身星抛射物碎片/突起,可能起源于前身星抛射物中的扰动。对于超新星遗迹W49B,我们首先研究了它的分子气体环境,发现了一个系统速度在～40kms-1的半圆形壳层分布的分子气体结构,包围了遗迹的东面,南面和西面。这与在遗迹东面,南面和西面观测到的射电波段的比较陡峭的边界和红外波段辐射分布(起源于遗迹与较密环境气体的作用)相一致。通过多波段形态的对应和(12CO J=2-1)/(12CO J=1-0)线比的增强,我们基本确认了遗迹与这个系统速度在～40kms-1的分子云的关联性,得到遗迹的运动学距离为9.3kpc。这里半圆形壳层分布的分子气体可能与超新星遗迹Kes 69中分子壳层的起源相同,是经由前身星星风扫积堆积而成。接下来,我们基于多波段观测结果建立了超新星遗迹W49B演化的理论模型,模型第一次考虑到了前身星抛射物与周围不均匀星周/星际介质的混合,热传导过程,光学薄等离子体的辐射损失过程,还有非电离平衡过程。我们发现热传导在超新星遗迹W49B的演化中起到重要作用,它导致了星周介质中云环物质的蒸发。这些被蒸发的较冷的云环物质与周围热气体的混合加快了降温过程,并且这些被蒸发的较冷的云环物质还将前身星抛射物推回了遗迹中心形成了喷流状结构。在模型演化中,发现了包含过电离等离子体的较大区域。这些过电离等离子体起源于被来自星周介质中云环的反弹激波再加热过的热等离子体的快速冷却。特别指出,我们发现了两种不同的快速冷却机制：热气体与由星周介质中云环物质蒸发而来的密度较大、温度较低的物质的混合；前身星抛射物的快速绝热膨胀。模型预期的过电离等离子体的空间分布与观测完全致。
[Abstract]:Supernova remnants are the product of the interaction between the precursors of the precursors and the surrounding interstellar medium during the supernova eruption. It will release a large amount of energy and metal elements into the interstellar medium and have an important influence on the physical and chemical evolution of the interstellar medium. In fact, many of the observational phenomena in the supernova remnants are derived from their interaction with the inhomogeneous INTERSTAR / interstellar medium, but the interaction between the supernova remnants and the inhomogeneous star / interstellar medium involves many complex physical processes, which makes the study of it. There are many difficulties. This article will introduce my work on the interaction between supernova remains and its surrounding interstellar medium. First, in the first chapter, a brief review of supernova, interstellar medium, strong shock physics, supernova remnants evolution, and so on, and then several representative cases: supernova are studied. The interaction between the remains and the molecular cloud (the supernova remnant Kes 69 is studied in the second chapter; the supernova remnant W49B), the interaction between supernova remnants and medium density clouds (in the third chapter, the supernova remnant Cygnus Loop), and the supernova remnants with a supernova phenomenon in the third chapter Evolution in the peripheral / interstellar medium (the supernova remnant W49B was studied in Section 4.3). The study involves the physical and chemical evolution of supernova remnants and clouds in different circumstances.
For the supernova remnant Kes 69, we confirm the association with the molecular cloud of the system velocity to 85kms-1, which allows us to get the kinematic distance of the remains of 5.2kpc. through the observation of 12CO (J=1-0) and the discovery of molecular cloud arcs in the southeast and northwest regions, which are highly distributed in a circle. These molecular gases are likely to be Through the front of the stars, the wind swept up.
For the supernova remnant Cygnus Loop, we studied the observation of a brighter area in the east of the XMM-Newton X Ray Telescope (called the XA region). The results show that the interstellar medium is denser and mass in this region, and it is also found that the C, N, O abundance of the interstellar medium is 0.2 times as much as two of the solar abundance. We apply a newly developed diagnostic tool to compare the spectral analysis and theoretical expectation, and confirm that the shock wave in this region plays a leading role in the evolution of the interaction between the clouds and the clouds. A precursor star projectile fragment / protrusion may originate from disturbances in the precursor star projectiles.
For the supernova remnant W49B, we first studied its molecular gas environment, and found a molecular gas structure of the semicircular shell distribution of the system at ~ 40kms-1, surrounded by the East, South and west of the remains. This is the steep boundary and infrared band of the radio band observed in the East, South and West of the remains. The distribution of radiation (originating from the effect of the remains and the denser ambient gas) is consistent. Through the enhancement of the multiband morphological correspondence and (12CO J=2-1) / (12CO J=1-0) line ratio, we have basically confirmed the correlation between the remains and the velocity of the system in the 40kms-1 molecular cloud, and the kinematic distance of the remains is the semicircular shell distribution here in 9.3kpc.. The molecular gas may be the same as the origin of the molecular shell in supernova remnant Kes 69, and is formed by the accumulation of precursor stars.
Next, we set up a theoretical model for the evolution of supernova remnant W49B based on the multiband observation. The model first considered the mixing of the precursors with the surrounding inhomogeneous star / interstellar medium, the heat conduction process, the radiation loss process of the optical thin plasma, and the non ionization equilibrium process. We found that the heat conduction is over the supernova. The evolution of the Nova remnant W49B plays an important role in the evaporation of the rings in the surrounding media. The cooling of these evaporated colder rings and the surrounding hot gases accelerates the cooling process, and the cooler clouds of the vaporized cloud also push the precursors back to the center of the remnant to form a jet structure. In the evolution of the model, the larger regions containing the over ionized plasma were found. These plasma were derived from the rapid cooling of the hot plasma reheated by the rebound shock from the ring of the surrounding media. In particular, we found two different rapid cooling mechanisms: the hot gas and the cloud ring in the star medium. The density of the vaporized matter, the mixture of the lower temperature, the rapid adiabatic expansion of the projectile of the precursor. The space distribution and observation of the expected over ionized plasma in the model are fully observed.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2011
【分类号】：P145.3

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