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You searched for +publisher:"University of Colorado" +contributor:("Ann-Marie Madigan"). Showing records 1 – 2 of 2 total matches.

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University of Colorado

1. Zetterlund, Erika Henning. Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane.

Degree: PhD, 2018, University of Colorado

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 <i>Herschel</i> 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°< Advisors/Committee Members: Jason Glenn, Jem Corcoran, Ann-Marie Madigan, Jeremy Darling, Benjamin Brown.

Subjects/Keywords: interstellar medium; milky way galaxy; herschel infrared galactic; galactic plane; molecular; Astrophysics and Astronomy; Stars, Interstellar Medium and the Galaxy

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APA (6th Edition):

Zetterlund, E. H. (2018). Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/astr_gradetds/55

Chicago Manual of Style (16th Edition):

Zetterlund, Erika Henning. “Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane.” 2018. Doctoral Dissertation, University of Colorado. Accessed January 28, 2020. https://scholar.colorado.edu/astr_gradetds/55.

MLA Handbook (7th Edition):

Zetterlund, Erika Henning. “Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane.” 2018. Web. 28 Jan 2020.

Vancouver:

Zetterlund EH. Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane. [Internet] [Doctoral dissertation]. University of Colorado; 2018. [cited 2020 Jan 28]. Available from: https://scholar.colorado.edu/astr_gradetds/55.

Council of Science Editors:

Zetterlund EH. Fuel for the Star Formation Engine: Dense Molecular Cloud Clumps in the Northern Galactic Plane. [Doctoral Dissertation]. University of Colorado; 2018. Available from: https://scholar.colorado.edu/astr_gradetds/55


University of Colorado

2. Rehnberg, Morgan Evan. Small-Scale Structure in Saturn's Rings.

Degree: PhD, 2017, University of Colorado

The rings of Saturn are the largest and most complex in the Solar System. Decades of observation from ground- and space-based observatories and spacecraft missions have revealed the broad structure of the rings and the intricate interactions between the planet’s moons and its rings. Stellar occultations observed by the Ultraviolet Imaging Spectrograph’s High Speed Photometer onboard the Cassini spacecraft now enable the direct study of the small-scale structure that results from these interactions. In this dissertation, I present three distinct phenomena resulting from the small-scale physics of the rings. Many resonance locations with Saturn’s external satellites lie within the main (A and B) rings. Two of these satellites, Janus and Epimetheus, have a unique co-orbital relationship and move radially to switch positions every 4.0 years. This motion also moves the resonance locations within the rings. As the spiral density waves created at these resonances interact, they launch an enormous solitary wave every eight years. I provide the first-ever observations of this never-predicted phenomenon and detail a possible formation mechanism. Previous studies have reported a population of kilometer-scale aggregates in Saturn’s F ring, which likely form as a result of self-gravitation between ring particles in Saturn’s Roche zone. I expand the known catalog of features in UVIS occultations and provide the first estimates of their density derived from comparisons with the A ring. These features are orders of magnitude less dense than previously believed, a fact which reconciles them with detections made by other means. Theory and indirect observations indicate that the smallest regular structures in the rings are wavelike aggregates called self-gravity wakes. Using the highest-resolution occulta- tions, I provide the first-ever direct detection of these features by identifying the gaps that represent the minima of the wakes. I demonstrate that the distribution of these gaps is con- sistent with the broad brightness asymmetries previously observed in the rings. Furthermore, the presence of spiral density waves affects the formation of self-gravity waves. Advisors/Committee Members: Larry Esposito, Nick Schneider, Dave Brain, Dan Scheeres, Ann-Marie Madigan.

Subjects/Keywords: planetary rings; Saturn; Astrophysics and Astronomy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Rehnberg, M. E. (2017). Small-Scale Structure in Saturn's Rings. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/astr_gradetds/49

Chicago Manual of Style (16th Edition):

Rehnberg, Morgan Evan. “Small-Scale Structure in Saturn's Rings.” 2017. Doctoral Dissertation, University of Colorado. Accessed January 28, 2020. https://scholar.colorado.edu/astr_gradetds/49.

MLA Handbook (7th Edition):

Rehnberg, Morgan Evan. “Small-Scale Structure in Saturn's Rings.” 2017. Web. 28 Jan 2020.

Vancouver:

Rehnberg ME. Small-Scale Structure in Saturn's Rings. [Internet] [Doctoral dissertation]. University of Colorado; 2017. [cited 2020 Jan 28]. Available from: https://scholar.colorado.edu/astr_gradetds/49.

Council of Science Editors:

Rehnberg ME. Small-Scale Structure in Saturn's Rings. [Doctoral Dissertation]. University of Colorado; 2017. Available from: https://scholar.colorado.edu/astr_gradetds/49

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