Open Access. Powered by Scholars. Published by Universities.®
Stars, Interstellar Medium and the Galaxy Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Applied Mathematics (2)
- Applied Statistics (1)
- Computer Sciences (1)
- Fluid Dynamics (1)
- Instrumentation (1)
-
- Non-linear Dynamics (1)
- Numerical Analysis and Computation (1)
- Numerical Analysis and Scientific Computing (1)
- Other Applied Mathematics (1)
- Other Physical Sciences and Mathematics (1)
- Partial Differential Equations (1)
- Physical Processes (1)
- Physics (1)
- Plasma and Beam Physics (1)
- Statistical Models (1)
- Statistics and Probability (1)
Articles 1 - 5 of 5
Full-Text Articles in Stars, Interstellar Medium and the Galaxy
The Magnetic Field Of Protostar-Disk-Outflow Systems, Mahmoud Sharkawi
The Magnetic Field Of Protostar-Disk-Outflow Systems, Mahmoud Sharkawi
Electronic Thesis and Dissertation Repository
Recent observations of protostellar cores reveal complex magnetic field configurations that are distorted in the innermost disk region. Unlike the prestellar phase, where the magnetic field geometry is simpler with an hourglass configuration, magnetic fields in the protostellar phase are sculpted by the formation of outflows and rapid rotation. This gives rise to a significant azimuthal (or toroidal) component that has not yet been analytically modelled in the literature. Moreover, the onset of outflows, which act as angular momentum transport mechanisms, have received considerable attention in the past few decades. Two mechanisms: 1) the driving by the gradient of a …
The Role Of Nonideal Magnetohydrodynamic Effects, Gravitational Instability, And Episodic Accretion In Star-Formation, Indrani Das
The Role Of Nonideal Magnetohydrodynamic Effects, Gravitational Instability, And Episodic Accretion In Star-Formation, Indrani Das
Electronic Thesis and Dissertation Repository
My dissertation focuses on the effect of magnetic fields on disk and core evolution during star-formation. We investigate the fragmentation scales of gravitational instability of a rotationally-supported self-gravitating protostellar disk using linear perturbation analysis in the presence of two nonideal magnetohydrodynamic (MHD) effects: Ohmic dissipation and ambipolar diffusion. Our results show that molecular clouds exhibit a preferred lengthscale for collapse that depends on mass-to-flux ratio, magnetic diffusivities, and the Toomre-Q parameter. In addition, the influence of the magnetic field on the preferred mass for collapse leads to a modified threshold for the fragmentation mass, as opposed to a Jeans mass, …
Point Process Modelling Of Objects In The Star Formation Complexes Of The M33 Galaxy, Dayi Li
Point Process Modelling Of Objects In The Star Formation Complexes Of The M33 Galaxy, Dayi Li
Electronic Thesis and Dissertation Repository
In this thesis, Gibbs point process (GPP) models are constructed to study the spatial distribution of objects in the star formation complexes of the M33 galaxy. The GPP models circumvent the limitations of the two-point correlation function employed in the current astronomy literature by naturally accounting for the inhomogeneous distribution of these objects. The spatial distribution of these objects serves as a sensitive probe in understanding the star formation process, which is crucial in understanding the formation of galaxies and the Universe. The objects under study include the CO filament structure, giant molecular clouds (GMCs) and young stellar cluster candidates …
Modeling The Mass Function Of Stellar Clusters Using The Modified Lognormal Power-Law Probability Distribution Function, Deepakshi Madaan
Modeling The Mass Function Of Stellar Clusters Using The Modified Lognormal Power-Law Probability Distribution Function, Deepakshi Madaan
Electronic Thesis and Dissertation Repository
We use the Modified Lognormal Power-law (MLP) probability distribution function to model the behaviour of the mass function (MF) of young and populous stellar populations in different environments. We begin by modeling the MF of NGC1711, a simple stellar population (SSP) in the Large Magellanic Cloud as a pilot case. We then use model selection criterion to differentiate between candidate models. Using the MLP we find that the stellar catalogue of NGC1711 follows a pure power-law behaviour below the completeness limit with the slope α = 2.75 for dN/dlnm ∝ m^(−α+1) in the mass range 0.89 M⊙ to 7.75 M⊙. …
Methods And Results Toward Measuring Magnetic Fields In Star-Forming Regions, Scott C. Jones
Methods And Results Toward Measuring Magnetic Fields In Star-Forming Regions, Scott C. Jones
Electronic Thesis and Dissertation Repository
Star formation is a fundamental process in the evolution of the cosmos. Yet given the abundance of stellar constituents, it remains prescient as to why the number of stars is not correspondingly large. If we cannot satisfactorily explain how stars are formed, then many further avenues of research are hindered. This thesis makes claims about one of the foremost theories as to the relative lack of stars, interstellar magnetic fields. These fields have been observationally verified on multiple scales. I will use the most direct method to probe magnetic fields in known star-forming regions, polarization, at millimetre/submillimetre wavelengths. In particular …