RUI: Experiments on Cooled Cosmic Dust Analogs to Determine their Optical Properties in the Millimeter/Sub-Millimeter

该项目将研究宇宙模拟尘埃在低温下的毫米/亚毫米光学特性。将购买一台干式制冷机，这样项目的工作就可以继续进行，而不需要购买易腐烂的制冷机。此外，专门为这项工作设计的傅里叶变换光谱仪将在PI的研究实验室建造。一旦这些仪器到位，将使用创新的研究程序测量许多内部或从外部组获得的灰尘样品的毫米/亚毫米不透明度和发射率。这项工作的主要目标是：(A)利用观测宇宙学界开发的丰富工具和专业知识，以前所未有的精度测量上述特性；(B)分析不同方法和不同研究人员在相同实验条件下产生的尘埃种类，以清楚地了解样品之间的共同趋势和基本差异；(C)实施一个有效的实验方案来分析大量的候选尘埃，这自然会导致建立一个关于测量属性的数据库。在可见光波段，尘埃掩盖了许多有趣的天文环境，如分子云、恒星形成区、被尘埃包裹的年轻和年老恒星，以及早期宇宙中年轻的超亮星系。毫米/亚毫米光谱区域是研究这些天体的一个很好的区域，因为尘埃在这些波长下更透明。关于星际尘埃性质的信息本身是有用的，因为尘埃是星系和恒星演化的重要组成部分，也是太空中复杂化学反应的重要组成部分，这些化学反应最终会产生益生元分子，这些信息可以揭示更多关于被尘埃掩盖的物体/环境的性质。最近的实验室研究表明，在毫米/亚毫米光谱区尘埃的性质比以前认为的要复杂得多。因此，在有把握地解释这些环境的天文数据之前，需要详细研究可以作为宇宙尘埃类似物的尘埃物种，比如将在这个项目中进行的那些。由于来自阿塔卡马大型毫米/亚毫米阵列等新天文台的高质量毫米/亚毫米数据的可用性，这种需求最近得到了加强。

This project will study the millimeter/sub-millimeter optical properties of cosmic analog dusts at low temperatures. A dry cryocooler will be purchased so that work on this project can continue, free from the expenses of perishable cryogens. In addition, a Fourier Transform Spectrometer, designed specifically for this work, will be constructed in PI's research lab. Once these apparati are in place, the mm/sub-mm opacity and emissivity of many dust samples, made internally or obtained from external groups will be measured, using an innovative program of study. The main goals of this work are to (A) utilize the rich set of tools and expertise developed within the observational cosmology community to measure the above properties to unprecedented accuracy, (B) analyze dust species produced by different methods and different investigators under the same experimental conditions in order to clearly understand common trends and basic difference between the samples, and (C) implement an efficient experimental scheme for analyzing a large number of dust candidates, which would naturally lead to the creation of a database on the measured properties.At visible wavelengths, dust obscures many interesting astronomical environments such as molecular clouds, star forming regions, young and old stars enveloped by dust, and young ultra-luminous galaxies in the early universe. The mm/sub-mm spectral region is a good regime to study these objects because dust is more transparent at these wavelengths. Information on the nature of interstellar dust is useful in and of itself because dust is an important component in galactic and stellar evolution as well as in the complex chemistry present in space that ultimately gives rise to prebiotic molecules, and this information can reveal more about the nature the objects/environments that are obscured by dust. Recent laboratory studies have shown that the properties of dust in the mm/sub-mm spectral region is more complicated than previously thought. Therefore, detailed studies dust species that can serve as analogs for cosmic dust such as those that will be undertaken in this project are needed before astronomical data on such environments can be interpreted with any confidence. This need has been intensified recently due to the availability high-quality mm/sub-mm data from new observatories such as the Atacama Large Millimeter/Submillimeter Array.