RUI: Completing Studies of Supernova Remnants and the Interstellar Medium

大质量恒星在灾难性的超新星爆炸中结束了它们的生命，释放的能量相当于太阳在其整个100亿年的寿命中所消耗的能量。 如此巨大的能量释放对超新星发生的星系产生了深远的影响。 例如，当冲击波遇到稠密的星际云时，它们可以触发星星形成的爆发。 超新星也负责宇宙中大多数重元素的产生和分布。 元素周期表上从碳到铁的几乎所有元素都是在大质量恒星的核心中形成的，并通过超新星爆炸分布在宇宙中。 这项研究的中心主题是更好地理解（1）超新星如何爆炸，（2）它们释放的巨大能量如何影响它们的宿主星系，以及（3）超新星如何促进宇宙中的化学变化。 研究人员和他们的学生将专注于银河系中选定的明亮超新星遗迹。 此外，他们还将研究附近星系中超新星遗迹的平均效应。 调查人员在米德尔伯里学院，这是佛蒙特州农村的一所种族多元化的学院。 研究者将与本科生合作，帮助他们发表研究成果。 研究人员还将通过将在大众文学和网络上发表的《发射线图集》中引人注目的图像与公众接触。该项目将特别关注年轻的超新星遗迹（SNRs），三十多年来的观测表明那里发生了显着的膨胀。 在未受污染的喷出物碎片自由膨胀的年轻的堆芯塌陷信噪比中，将使用图像和光谱数据来获得数十个幸存的喷出物结的自行和多普勒速度，以获得三维模型并探索可能的不对称性。 从光谱中推断出的化学丰度可以将目前的结与祖先恒星特定核心层的起源联系起来。 在年轻的Ia型超新星中，特别是Tycho（SN 1572）和RCW 86（SN 185），将测量Balmer主导的细丝的自行，描绘它们的外壳，以衡量它们的扩张。 这两个物体中大量细丝的高信噪比光谱将能够确定激波速度，这与自行一起可以产生到这些关键物体的第一个精确距离。 研究人员还将统计调查整个星系中大SNR群体的特性，在那里可以看到SNR不受前景尘埃的阻碍，这些尘埃隐藏了银河系中大多数SNR。 研究人员和合作者将确定过去世纪超新星最多的两个附近星系中的SNR种群。

Massive stars end their lives in catastrophic supernova explosions, releasing as much energy as the Sun will expend throughout its entire 10-billion-year lifetime. Such an enormous energy release has profound effects on the galaxies where supernovae occur. For example, the shock waves can trigger bursts of star formation when they encounter dense interstellar clouds. Supernovae are also responsible for the production and distribution of most of the heavy elements in the Universe. Virtually all elements from carbon to iron on the periodic table were forged in the cores of massive stars and distributed around the cosmos through supernova explosions. The central themes of this research are to better understand (1) how supernovae explode, (2) how their huge energy release affects their host galaxies, and (3) how supernovae contribute to the chemical changes in the Universe. The investigator and their students will focus on selected bright supernova remnants in the Milky Way. Also, they will study the average effect of supernova remnants in the nearby galaxies. The investigator is at Middlebury College, an ethnically diverse college in rural Vermont. The investigator will work with undergraduate students and help them publish their research results. The investigator will also reach out to the public via the striking images from the Emission Line Atlas to be published in popular literature and on the web.This project will concentrate especially on young supernova remnants (SNRs), where observations made over three decades reveal significant expansion. In young core-collapse SNRs, where uncontaminated ejecta fragments are freely expanding, image and spectroscopy data will be used to obtain proper motions and Doppler velocities for dozens of surviving ejecta knots to obtain 3-dimensional models and explore possible asymmetries. Chemical abundances inferred from spectra can tie present knots to their origin in specific core layers of the progenitor stars. In young Type Ia SNRs, specifically Tycho (SN1572) and RCW86 (SN185), proper motions of Balmer-dominated filaments that delineate their outer shells will be measured to gauge their expansion. High signal-to-noise spectra of numerous filaments in both objects will enable determination of the shock velocities, which together with proper motions can yield the first precise distances to these key objects. The investigator will also statistically investigate the properties of large SNR populations in an entire galaxy, where SNRs can be seen unimpeded by the foreground dust that hides from view most SNRs in the Milky Way. The investigator and collaborators will identify the SNR populations in the two nearby galaxies which had the most supernovae in the past century.