RUI: Observational Studies of Galactic and Extragalactic Supernova Remnants

摘要文克勒超新星是大质量恒星(质量约为太阳的8倍)结束生命的灾难性事件。它们是目前宇宙中发生的能量最高的局部化事件：典型的超新星爆炸在几秒钟内释放出约10次方焦耳的能量，相当于太阳在其100亿年寿命的整个过程中所消耗的能量。毫不奇怪，如此惊人的能量释放可以对发生超新星的星系的动力学产生深远的影响。超新星产生的冲击波被认为在遇到稠密的星际云时会触发恒星的形成。此外，超新星负责宇宙中大多数重元素的生产和分配。在元素周期表上，从氦到铁，几乎所有的元素都是通过大质量恒星核心的核合成而产生的，这些元素通过最初形成它们的恒星的超新星爆炸分布在宇宙中。通过研究超新星及其留下的残留物，我们可以深入了解核合成的过程，宇宙化学成分的演变，以及如此巨大的能量释放对超新星宿主星系的影响。超新星残骸(SNR)的银河系外样本比我们银河系内的样本有两个显著的优势：(I)对其他星系的观察受到星际吸收的阻碍比在银河系要小得多，在银河系中，只有不到三分之一的已知残骸被光学手段探测到；(2)另一个星系的所有残骸都在相同的已知距离，这使得它们之间的比较更有意义和可靠。在距离我们银河系最近的大小麦哲伦星云以及本星系群中最大的星系M31中进行的超新星搜索，应该会使这些星系中SNR的样本增加几倍。将使用Kitt Peak和Cerro Tololo天文台的小型施密特望远镜上的CCD相机进行广视场数字成像。这项技术已经导致了100多个SNR候选者的识别。这些候选超新星将通过光谱学和高分辨率成像进一步研究，以确认它们是否真的是SNR，然后将观察它们的性质。扩展的河外SNR样本将用于研究超新星的局域环境，探测星系中的元素丰度和丰度梯度，测量超新星事件的能量，并研究超新星对星系结构的影响。详细的关注将集中在少数年轻的SNR上，在那里可以识别出超新星未受污染的喷射物。在数量更多的较老的残骸中，通过星际介质驱动的冲击波可以探测星际气体的密度、结构和丰度。广域成像技术将被用来以前所未有的细节研究我们银河系中的单个SNR。拟议的光学调查将与新的射电和X射线数据相结合，以研究超新星的星际环境和冲击波的基本物理。这些对几个选定天体的详细研究将补充更广泛的河外调查。与本科生的重大合作是开展这项研究不可或缺的一部分。

Abstract Winkler Supernovae are the cataclysmic events in which massive stars (more than about 8 times the mass of our Sun) end their lives. They are the most energetic localized events which now occur in the universe: a typical supernova explosion releases in a few seconds an energy of about 10 to the 44th Joules, comparable to what the Sun will expend throughout the entire course of its 10 billion year lifetime. Not surprisingly, such a prodigious release of energy can have profound effects on the dynamics of galaxies in which supernovae occur. The shock waves from supernovae are believed to trigger episodes of star formation when they encounter dense interstellar clouds. Furthermore, supernovae are responsible for the production and distribution of most of the heavy elements in the universe. Virtually all the elements from helium to iron, on the periodic table, were created by nucleosynthesis in the cores of massive stars, and these elements have been distributed around the cosmos through the supernova explosions of the stars in which they were originally formed. By studying supernovae and the remnants they leave behind, we can gain insight into the processes of nucleosynthesis, the evolution of the universe's chemical composition, and the effects of such prodigious energy release on the host galaxies of supernovae. Extragalactic samples of supernova remnants (SNRs) offer two significant advantages over ones in our Galaxy: (I) the view toward other galaxies is far less impeded by interstellar absorption than in the Milky Way, where fewer than a third of all known remnants have been detected at all by optical means, and (2) all the remnants in another galaxy are at the same, known distance, making comparisons among them much more meaningful and reliable. Supernovae searches to be conducted in the Large and Small Magellanic Clouds, nearest neighbors to our Milky Way, and in M31, the largest galaxy in the Local Group, should increase the samples of SNRs in t hese galaxies several-fold. Wide-field digital imaging through the use of CCD cameras on small Schmidt telescopes at Kitt Peak and Cerro Tololo observatories will be used. A technique which has already led to the identification of over 100 SNR candidates. These supernovae candidates will be further studied through spectroscopy and high-resolution imaging to confirm whether they are, in fact, SNRs and then their properties will be observed. The expanded extragalactic SNR samples will be used to study the local environments of supernovae, to probe elemental abundances and abundance gradients in galaxies, to measure the energy of supernova events, and to study the effects of supernovae on galactic structure. Detailed attention will be focused on the handful of young SNRs where uncontaminated ejecta from the supernova can be identified. In older remnants, which are much more numerous, shocks driven through the interstellar medium can probe the density, structure, and abundances of the interstellar gas. Wide-field imaging techniques will be used to study individual SNRs in our Galaxy in unprecedented detail. The proposed optical investigations will be combined with new radio and X-ray data to study the interstellar environments of supernovae and the fundamental physics of shocks. These detailed studies of a few selected objects will complement the broader extragalactic surveys. Significant collaboration with undergraduate students is integral to carrying out the research.