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Articles 1 - 5 of 5
Full-Text Articles in Physical Processes
A New Galactic Wind Model For Cosmological Simulations, Shuiyao Huang
A New Galactic Wind Model For Cosmological Simulations, Shuiyao Huang
Doctoral Dissertations
The propagation and evolution of cold galactic winds in galactic haloes is crucial to galaxy formation models. However, modelling of this process in hydrodynamic simulations of galaxy formation is over-simplified owing to a lack of numerical resolution and often neglects critical physical processes such as hydrodynamic instabilities and thermal conduction. In this thesis, I propose an analytic model, Physically Evolved Winds (PhEW), that calculates the evolution of individual clouds moving supersonically through a uniform ambient medium. The model reproduces predictions from very high resolution cloud-crushing simulations that include isotropic thermal conduction over a wide range of physical conditions. I also …
Observational Studies Of Fragmentation In Molecular Clouds, Riwaj Pokhrel
Observational Studies Of Fragmentation In Molecular Clouds, Riwaj Pokhrel
Doctoral Dissertations
In this dissertation, I explore fragmentation physics in multiple scales in nearby molecular clouds and discuss some implications of fragmentation for cloud structure formation and star formation, primarily by analyzing multi-wavelength observations of dust emission. First, I tested the complete thermal and combined thermal and nonthermal support mechanisms that balance gravitational contraction at multiple scales in the Perseus molecular cloud. I found that the observed multiscale structures in Perseus are consistent with an inefficient thermal Jeans fragmentation, where the Jeans efficiency increases from the largest scale ($\gtrsim$10s of pc) to the smallest scale ($\sim$10s of AU). Next, I studied the …
The Non-Linear Dynamics Of Barred Galaxy Evolution In Lcdm, Michael Petersen
The Non-Linear Dynamics Of Barred Galaxy Evolution In Lcdm, Michael Petersen
Doctoral Dissertations
The study of barred galaxy dynamics has had many successes explaining observed phenomena in barred galaxies both locally and distant, including our own Milky Way, a barred galaxy. However, the majority of this knowledge arises from either (a) analytic linear theory, which by definition cannot inform nonlinear processes, or (b) simulations which are subject to an unconstrained host of evolutionary mechanisms, including `real' dynamical processes and `artificial' numerical processes, and are thus difficult to interpret. This work chooses a path which attempts to take the best of both techniques, employing n-body simulations in the Lambda cold dark matter paradigm designed …
Astrophysical Accretion And Feedback: The Bayesian Linchpin Of Theory And Observation, Shawn Roberts
Astrophysical Accretion And Feedback: The Bayesian Linchpin Of Theory And Observation, Shawn Roberts
Doctoral Dissertations
Despite being a major pillar of galaxy evolution, galactic feedback from stars and supermassive black holes (SMBHs) is subject to very little observational constraint. This is particularly true of the hot component, as viewed in X-rays. Yet, the hot component is directly linked to much of the energetic feedback released from these compact objects. X-ray observations suffer from several challenges that make placing this constraint a difficult task. In the face of considerable model uncertainty, these challenges underscore the need for novel X-ray data analysis techniques. In this dissertation, I seek to lend a unique perspective to X-ray data analysis …
The Cosmic Web, And The Role Of Environment In Galaxy Evolution, Ryan Cybulski
The Cosmic Web, And The Role Of Environment In Galaxy Evolution, Ryan Cybulski
Doctoral Dissertations
The Universe, on extra-galactic scales, is composed of a vast network of structures dubbed the “cosmic web”. One of the most fundamental discoveries about the evolution of galaxies is that their properties have a dependence on their location relative to this cosmic web (i.e., their environment). However, detailed studies of the environmental dependence on galaxy evolution have been extremely challenging due to the inherent complexity of the structures on the largest scales, a plethora of techniques being used to try to map the cosmic web, and other confounding factors, such as the masses of galaxies, that also affect their evolution. …