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.
