星际未认证红外谱带载体结构与天体环境的关系

发布时间：2018-05-31 18:05

本文选题：未认证红外光谱 + 载体　；参考：《湘潭大学》2016年硕士论文

【摘要】：未认证红外光谱(Unidentified Infrared Emission,UIE)在星际中被广泛观测到,其辐射能量约占银河系红外辐射总量的20%。至今发射UIE的载体性质仍不明确。第一部分工作,我们找出了数十个同时具有3.3μm和3.4μm特征谱线的UIE源。而后利用GetData Graph Digitizer软件将这些光谱图片进行数字化,获得UIE源的光谱,并利用连续谱叠加若干洛仑兹(Lorentz)线模型拟合这些光谱,从而得到3.3μm和3.4μm谱征的流量比I3.4/I3.3。拟合结果表明,大多数UIE天体都是代表芳香性的3.3μm谱征比代表脂肪性的3.4μm谱征要强,只有少数几个天体是3.4μm谱征比3.3μm要强。我们猜想造成I3.4/I3.3不同的原因可能跟这些UIE源所处的天体环境有关。于是,我们搜集了所有UIE源的天体环境数据,包括中心天体温度(代表星光硬度)和星光强度,从而研究UIE载体结构(脂肪度)与天体环境的关系。从我们给出的I3.4/I3.3与恒星温度的相关性图上可以看到,I3.4/I3.3越大,其中心天体的有效温度越低,这些源通常是YSO这一类型的天体。对于HII/CHII这一类UIE源天体,其中心天体的有效温度变化很少,但I3.4/I3.3的比值却差异很大。这一结果表明UIE载体脂肪度确实与星光硬度有关,但并不是一一对应关系。第二部分工作,我们利用Chandra卫星的观测数据对Tycho超新星遗迹进行高空间分辨能谱分析。我们将超新星遗迹划分为500余个区域,对每一个区域产生光谱并进行拟合,从而得到了其吸收柱密度图、平均温度、电离年龄、以及O、Ne、Mg、Si、S、Fe丰度的空间分布图。从Fe空间分布图我们发现铁比其它元素出现的区域半径更小,而从丰度图上可以看到Fe的丰度与其他元素丰度没有相关性,这佐证了“洋葱”模型,即重元素分布在更中心的位置,而随着元素越来越轻,其分布的半径也越来越大。Si和S的丰度呈现很好的正相关关系,表明Si和S来源于爆炸性O燃烧或不完全爆炸性Si燃烧。根据丰度图显示,O和Ne的丰度与其它元素没有关联。考虑到O、Ne和Mg都是在同一个过程中合成的,我们认为O/Ne/Mg和其它元素在超新星爆发或超新星遗迹膨胀过程中中发生了混合。在SNR的北部和西部我们发现了相对于几何中心和爆发中心以非球形分布的非热暗条,这表明Tycho’s SN的爆发可能是不对称的。
[Abstract]:Unidentified Infrared emission UIEs have been widely observed in the interstellar region, and their radiation energy accounts for about 20% of the total infrared radiation in the Milky way. Up to now, the properties of UIE carrier are still unclear. In the first part, we find out dozens of UIE sources with 3. 3 渭 m and 3. 4 渭 m characteristic lines at the same time. Then the spectra of the UIE source are digitized by using GetData Graph Digitizer software, and the spectra of the UIE source are fitted by the continuous spectrum superposition of some Lorentz Lorentzline models, and the flow rate of 3.3 渭 m and 3.4 渭 m spectra is obtained compared with that of I 3.4 渭 m I 3.4 / I 3.3. The fitting results show that most UIE objects are 3. 3 渭 m spectral characteristics representing aromaticity, and only a few are 3. 4 渭 m spectral characteristics stronger than 3. 3 渭 m spectral characteristics. We suspect that the different causes of I3.4/I3.3 may be related to the celestial environment in which these UIE sources are located. Therefore, we collected all the data of celestial environment of UIE source, including the central celestial body temperature (representing star hardness) and starlight intensity, so as to study the relationship between the structure of UIE carrier (degree of fat) and celestial environment. From the diagram of the correlation between I3.4/I3.3 and star temperature, we can see that the larger the I3.4 / I3.3, the lower the effective temperature of the central celestial body. These sources are usually YSO objects. For UIE source objects such as HII/CHII, there is little change in the effective temperature of the central body, but the ratio of I3.4/I3.3 varies greatly. The results show that the fat degree of UIE carrier is really related to starlight hardness, but it is not a one-to-one correspondence. In the second part, we use the observation data of Chandra satellite to analyze the high spatial resolution energy spectrum of Tycho supernova remnant. The supernova remains are divided into more than 500 regions. The spectra of each region are generated and fitted to obtain the spatial distribution of the absorption column density map, mean temperature, ionization age and the abundance of SzcFe in the supernova. From the spatial distribution map of Fe, we find that the radius of the region of iron is smaller than that of other elements, but the abundance of Fe is not related to the abundance of other elements from the map of abundance, which supports the "onion" model. That is to say, the distribution of heavy elements is in the more central position, and as the elements become lighter and lighter, the distribution radius of Si and S show a good positive correlation with the abundance of S, indicating that Si and S originate from explosive O combustion or incomplete explosive Si combustion. The abundance of O and ne is not related to other elements according to the abundance diagram. Considering that ONe and mg are synthesized in the same process, we think that O/Ne/Mg and other elements are mixed during supernova explosion or supernova relic expansion. In the north and west of SNR, we have found the non-spherical distribution of the non-thermal dark strip relative to the geometric center and the explosion center, which indicates that the burst of Tycho's SN may be asymmetrical.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P141.5

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