Date of Award

Spring 1-1-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Jason Glenn

Second Advisor

Jem Corcoran

Third Advisor

Ann-Marie Madigan

Fourth Advisor

Jeremy Darling

Fifth Advisor

Benjamin Brown

Abstract

The interstellar medium (ISM) is a confusing, muddled place. It provides the fuel for star formation, but before that can occur, the ISM must cool and condense into molecular clouds. Even this is not enough, however. It is only the cores, contained within the clumps, contained within the clouds, which form stars. With all these nested structures, it takes an optically thin, yet still bright, tracer to uncover the processes which convert the molecular clouds into stars. Luckily, the ISM is dusty.

I use the Herschel infrared GALactic plane survey (Hi-GAL) to study molecular cloud clumps through their thermal dust emission at 500 μm. For adapting and testing the clump identification and distance techniques – developed for the Bolocam Galactic Plane Survey (BGPS) – I used six Hi-GAL maps at a representative sample of Galactic longitudes. I found many more clumps per square degree with Hi-GAL than were identified with BGPS, particularly at longitudes farther from the Galactic center, where Hi-GAL's increased sensitivity truly shines. Where I found the same clumps as BGPS, my distances and physical properties aligned well. Notably, clumps are slightly larger in Hi-GAL, where the diffuse edges are not overtaken by atmospheric noise, as was the case with BGPS.

The application of these techniques to 10°

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