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FUV Spectroscopy of Interstellar and Circumstellar Material

Posted on:2012-04-08Degree:Ph.DType:Dissertation
University:University of Colorado at BoulderCandidate:Schindhelm, Eric RobertFull Text:PDF
GTID:1451390008991179Subject:Physics
Abstract/Summary:
I have designed, assembled, and calibrated a sounding rocket payload to perform high resolution FUV spectroscropy. Debate lingers over the existence of a pervasive 1 million K gas in our region of the interstellar medium, the Local Bubble. If this hot gas were present, it would produce O VI upon interacting with the cold cavity wall. As such, O VI serves as a diagnostic for the hot interstellar gas. I designed the Diffuse Interstellar Cloud Experiment (DICE) to measure the O VI (1032,1038 Angstrom) doublet in absorption against two stars on either side of the Local Bubble wall. The instrument is functionally a Cassegrain telescope followed by a modified Rowland-mount spectrograph. With a holographically-ruled grating and a secondary magnifying optic, the spectrograph can achieve high resolving power (R=60,000) in a compact space.;In addition, I have analyzed Carbon Monoxide (CO) emission from Classical T-Tauri star disks using spectra from the HST-Cosmic Origins Spectrograph. The CO is photo-excited by Lyman alpha from the magnetospheric shock. I model this incident Lyman alpha radiation to use as input for a simple CO fluorescence model. Fits to the data constrain CO temperatures and column densities, which can then be compared with other known properties of the disks in our target sample. I find no correlation between this UV-emitting CO and the CO studied at infrared and sub-mm wavelengths between targets.
Keywords/Search Tags:Interstellar
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