分子云环境中的超新星遗迹

发布时间：2018-06-17 01:15

本文选题：超新星遗迹 + 分子云　；参考：《南京大学》2014年博士论文

【摘要】：大质量恒星形成于分子云中致密云核的坍缩,而其演化最后终结于核坍缩超新星爆发。在这些恒星短暂的一生中,它们强烈的星风和电离辐射能清空出一个腔体。若其存在环境分子云,我们就可能观测到超新星遗迹撞击腔壁分子气体。超新星遗迹与分子云的相互作用对于研究稠密气体的物理和化学过程,追溯前身星演化,探索宇宙线强子作用都具有重要意义。我的博士论文针对分子云环境中的超新星遗迹Kes78.Kes79和W28进行了多波段的观测研究,并理论上探讨了分子云内空腔与前身星质量的关系。以超新星遗迹Kes78为起点,我们研究了该遗迹的分子云环境并开展了对其东北壳层的XMM-Newton X射线光谱分析。通过CO三个跃迁的观测,我们建立了遗迹与～81km s-1的分子云腔体相互作用的证据,包括展宽的12CO谱线和相对增强的12CO J=2-1/J=1-0比例。我们还探明了其环境分子云分布,并为探究其强子伽玛射线辐射提供指引。Kes78东北壳层上的X射线来自亚电离的热(～1.5keV)气体,其密度为-0.1cm-3,可能是团际介质。遗迹的年龄约为6kyr。根据分子云腔体的大小,我们估算出其前身星的初始质量约为21M(?)。在一些超新星遗迹周围出现的腔状和弧状分子云使我们意识到,前身星星风对分子云的塑造也许能有助于研究其前身星质量。我们发现分子云环境中的大质量恒星的主序星风泡大小与恒星质量存在一个接近线性的关系Rb≈1.22M/M⊙-9.16pc。由于8到25-30M(?)的恒星的演化会进入红超巨星阶段而不产生Wolf-Rayet星风,主序阶段的星风泡就决定了分子云腔体的尺度。而相比起来,光致电离的影响却很小。该关系为分子云腔体中的超新星遗迹提供了一种难得的诊断前身星质量的新工具。利用这个关系,我们估算了8个超新星遗迹的前身星质量：Kes69,Kes75,Kes78,3C396,3C397,HC40,Vela和RXJ1713-3946。热混合型超新星遗迹往往与分子云相互作用,由于这类遗迹具有诸多有趣却未得到解释的观测特征,是近年观测和研究的热点。W28作为热混合型超新星遗迹的原型,其热混合型形态起源还不清楚。我们开展了对W28的XMM-Newton成图和光谱研究。遗迹内部的X射线辐射是非均匀的,一个冷的非电离平衡等离子体和一个达到碰撞电离平衡的热气体的组合能最好地解释观测到的X射线。这个双温模型下,冷的亚电离的成分来自蒸发的团块气体。多个观测证据支持W28内部存在小云团的蒸发过程,而这个过程或许可以解释遗迹的热混合型形态。我们将这个双温模型应用到不同的小区域中,发现吸收、温度和密度在遗迹内的分布是随空间变化的,说明遗迹在一个不均匀的环境中演化,而更密的介质在遗迹的东部和北部。除了双温模型,遗迹内部的X射线还可能用电子温度为0.6keV的过电离气体模型来描述。过电离气体的复合时标约为2.9×104yr,接近遗迹的动力学年龄。W28东北壳层上的X射线存在一个0.3keV的低温成分,而硬X射线可能是热起源(温度～0.61keV)也可能是非热起源(光子谱指数～2)。若为非热起源,非热电子经受库伦损失的韧致辐射是最可能的解释。通过开展CO观测,我们给出了热混合型超新星遗迹Kes79与～105kms-1分子云作用的运动学证据。Kes79在X射线波段存在丰富的明亮丝状结构以及一个弥散的暗晕。遗迹整体的X射线辐射需要用双温(0.23+1.05keV)的模型来描述,其高温成分存在S和Ar的超丰,说明了抛射物的存在。在西北射电内壳层外,我们发现一个X射线团块具有不寻常的高温(2.0-0.4+0.5keV)和增丰的Mg, Si, S和Ar。暗晕的气体与明亮丝状结构不同,金属丰度趋于甚至低于太阳丰度。在边缘区域,暗晕的X射线辐射用一个高温成分(0.9-1.4keV)就可以解释。我们研究了遗迹的整体演化性质,得到遗迹的激波速度为833-12+3km s-1,年龄为～5.8kyr。对比多波段分析结果,我们认为遗迹的双壳层结构和热混合型形态都是投影效应。根据遗迹分子云腔的大小和抛射物中金属元素的丰度,我们估算出其前身星是质量为～12Me的B1型星。在研究Kes79的过程中,我们幸运地在其南部发现了一颗11.56s的X射线脉冲星3XMM J185246.6+003317。根据其自转减慢速率1.1×10-13s s-1和周期11.5587126(4)s可以得到脉冲星的表面偶极磁场3.6×1013G,特征年龄1.7Myr,自转能损2.8×1030erg s--1。通过对它的X射线光谱分析,我们发现共振回旋散射模型能给出最佳拟合,同时,黑体辐射也可以描述X射线光谱。从2008年到2009年总共7个月的观测中,该脉冲星的的光谱性质发生了剧烈的变化：其光度由2.7×1034erg s-1降至4.6×1033erg s-1,而黑体辐射温度由约0.8keV降至月0.6keV。3XMM J185246.6+003317的X射线光度远远高于其自转能损,排除了由自转供能的可能。它在光学和红外波没有探测到对应天体,而且2008年之前的多次X射线观测中它都没有出现,再结合时序和光谱分析,我们认为3XMM J185246.6+003317是一颗新发现的暂现低磁磁星,而它在2008年的一次爆发正好被XMM-Newton观测到。2001年Chandra对它的观测将它的宁静光度上限限制到4×1032erg s--1。由于该磁星与Kes79的吸收柱密度类似,可以认为它们处于相似的距离～7.1kpc上。它是目前自转最慢的暂现强磁星,也是第三颗已知低磁强磁星。3XMM J185246.6+003317与其北部的超新星遗迹Kes79和遗迹内部反磁星是否存在可能的物理联系则需要未来的观测给出确定性的答案。
[Abstract]:Large mass stars form in the collapse of dense cloud nuclei in molecular clouds, and their evolution ends in the end of nuclear collapse supernova. In the short lifetime of these stars, their strong stellar winds and ionizing radiation can empty out a cavity. If there is an environmental molecular cloud, we may observe the molecular gas of the supernova remnant impacting the wall of the cavity. The interaction between supernova and molecular clouds is of great significance in studying the physical and chemical processes of dense gas, tracing the evolution of the precursors and exploring the role of the cosmic ray hadron.
My doctoral thesis has conducted a multi band observation study of supernova remnants Kes78.Kes79 and W28 in the molecular cloud environment, and theoretically discussed the relationship between the cavity of the molecular cloud and the mass of the precursor.
Taking the supernova remnant Kes78 as the starting point, we studied the molecular cloud environment of the remains and analyzed the XMM-Newton X ray spectra of its northeastern shell. By observing the three transitions of CO, we established the evidence for the interaction between the remains and the molecular cloud cavity of 81km s-1, including the broadened 12CO spectrum and the relatively enhanced 12CO J=2-1/J. =1-0 ratio. We also explore the distribution of its environmental molecular cloud and provide guidance to explore its hadronic gamma ray radiation to guide the X rays from the.Kes78 shell of the northeastern shell from subionized heat (to 1.5keV). The density is -0.1cm-3 and may be an intergroup medium. The age of the remnant is about 6kyr. based on the size of the molecular cloud cavity, and we estimate its predecessor The initial mass of a star is about 21M (?).
The cavity and arc molecular clouds appearing around some supernova remnants make us aware that the molding of the precursor to the molecular clouds may help to study the mass of the precursors. We found that the size of the main stars in the mass stars in the molecular cloud environment is in a close linear relationship with the mass of the stars, Rb 1.22M/M -9. 16pc. because the evolution of 8 to 25-30M (?) stars will enter the red supergiant stage and does not produce the Wolf-Rayet star wind, the main sequence stage star bubble determines the scale of the molecular cloud cavity. Compared with the photoionization, the effect of the photoionization is very small. This relationship provides a rare diagnostic precursor star quality in the supernova remnant of the molecular cloud cavity. Using this relationship, we estimate the precursor mass of 8 supernova remnants: Kes69, Kes75, Kes78,3C396,3C397, HC40, Vela and RXJ1713-3946..
Hot mixed supernova remains often interact with molecular clouds. Because these sites have many interesting but unexplained observational features, it is a hot spot of.W28 as a prototype of hot mixed supernova remnants in recent years. The origin of the thermal hybrid form is not clear. We have carried out the XMM-Newton mapping and spectrum of W28. Research. The X ray radiation inside the site is heterogeneous, and a cold non ionized equilibrium plasma and a combination of thermal gases that reach the collision ionization equilibrium can best explain the observed X rays. Under this double temperature model, the cold subionization component comes from the evaporated mass of gas. Several observations support the existence of small internal presence in W28. The process of vaporization of clouds may explain the thermal mixed form of the remains. We apply this double temperature model to different cell domains and find that the distribution of absorption, temperature and density varies with space in the remains, indicating the evolution of the remains in an uneven environment, and the denser medium in the east of the remains. In addition to the north, in addition to the double temperature model, the X ray inside the remains may also be described with an over ionized gas model of the electron temperature of 0.6keV. The composite time of the over ionized gas is about 2.9 x 104yr, close to the kinetic age of the remnant.W28, and the X ray on the northeastern shell has a 0.3keV low temperature component, while the hard X ray may be the thermal origin (temperature ~ (temperature). 0.61keV) may also be non thermal origin (photon spectral index 2). If it is non thermal origin, the most probable explanation for the loss of bremsstrahlung in the non thermal electrons is Kulun.
Through the CO observation, we give the kinematic evidence for the action of the thermal mixed supernova remnant Kes79 and the 105kms-1 molecular cloud..Kes79 is rich in the bright filamentous structure and a diffuse dark halo in the X ray band. The X ray radiation of the whole remains is described by the model of the double temperature (0.23+ 1.05keV), and its high temperature composition exists in S and in the presence of S. Ar's super abundance shows the existence of a projectile. Outside the inner shell of the northwest radio, we found that a X ray mass with unusual high temperature (2.0-0.4+0.5keV) and added Mg, Si, S and Ar. is different from the bright filamentous structure, and the metal abundance tends to be even lower than the solar abundance. In the marginal region, the X ray radiation of the faint halo is used in one The high temperature component (0.9-1.4keV) can be explained. We have studied the whole evolution properties of the remains. The shock wave velocity of the remains is 833-12+3km s-1, and the age of ~ 5.8kyr. contrast multi band analysis results. We think that the double shell structure and the thermal mixed form of the remains are all projection effects. We estimate that the precursor of the metal element is B1 star with mass of 12Me.
In the study of Kes79, we luckily found a 11.56s X ray pulsar 3XMM J185246.6+003317. in its southern part, which can get the surface dipole magnetic field of the pulsar by its rotation and slow rate of 1.1 x 10-13s S-1 and the period 11.5587126 (4) s. The characteristic age 1.7Myr, the rotation energy loss of 2.8 * 1030erg s--1. through it We found that the resonance cyclotron scattering model can give the best fitting, and the blackbody radiation can also describe the X ray spectrum. From 2008 to 2009, the spectral properties of the pulsar changed dramatically: the luminosity from 2.7 x S-1 to 4.6 x 1033erg s-1, and the black body radiation temperature. The X ray luminosity from about 0.8keV to 0.6keV.3XMM J185246.6+003317 is far higher than its rotation energy loss, excluding the possibility of rotation energy supply. It has not detected the corresponding celestial bodies in the optical and infrared waves, and it did not appear in the multiple X ray observations before 2008, and then combined with time series and spectral analysis, we think 3XMM J18524 6.6+003317 is a newly discovered temporary low magnetic magnetic star, and its outbreak in 2008 was just observed by XMM-Newton to.2001 Chandra for its observation to limit its tranquil photometric upper limit to 4 x 1032erg s--1. because the magnetic star is similar to the density of the absorption column of Kes79, and it is considered to be at a similar distance to 7.1kpc. At present, the slowest rotation of the magnetic star, and the possible physical link between the third known low magnetic strong magnetic stars.3XMM J185246.6+003317 and the supernova remnant Kes79 in the north and the internal antimagnetic stars in the remains, will require definite answers to future observations.
【学位授予单位】：南京大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P145.3

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