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Full-Text Articles in Astrophysics and Astronomy

Probing The Physical Mechanisms Responsible For Brown Dwarf And Giant Planet Formation, Sarah Betti Nov 2023

Probing The Physical Mechanisms Responsible For Brown Dwarf And Giant Planet Formation, Sarah Betti

Doctoral Dissertations

The disks that form around young stellar objects provide the essential material for their continued growth as well as the formation of planets, making them ideal laboratories to investigate the mechanisms and environments key for substellar and planetary formation. In this dissertation, I explore two main formation processes: the transportation of water necessary for giant planet formation, and the accretion and growth of young brown dwarfs. First, I study the water ice content in the circumstellar disk of AB Aurigae, a young Herbig Ae star. I detect and map icy grains on the disk surface using high contrast observations taken …


Sub-Chandrasekhar Type Ia Supernovae Scenarios With Increased Pathways For Neutronization, Fernando Hernan Rivas May 2023

Sub-Chandrasekhar Type Ia Supernovae Scenarios With Increased Pathways For Neutronization, Fernando Hernan Rivas

Doctoral Dissertations

Type Ia supernovae are thermonuclear explosions of white dwarfs (WD), electron-degenerate cores of old intermediate mass stars(under 8$M_{\odot}$). Reaching energies of $10^{51}$\si{\erg}, they outshine whole galaxies as they synthesize and distribute most of the iron group elements (IGE; V, Cr, Mn, Fe, Co, Ni) into the interstellar medium, thus being one of the main agents in cosmic chemical evolution. Also, given their notably homogeneous lightcurves, they form the last step in the cosmic distance ladder outdistancing Cepheid variables by orders of magnitude. Though calibration of said lightcurves is dependent on a high number of confirmed events, the limits of statistical …


The Coeval Mass Assembly Of The Universe Via Supermassive Black Hole Accretion And Star Formation In Galaxies, Alyssa Sokol Apr 2023

The Coeval Mass Assembly Of The Universe Via Supermassive Black Hole Accretion And Star Formation In Galaxies, Alyssa Sokol

Doctoral Dissertations

The possible co-evolution between galaxies and their central supermassive black holes is supported by the similarity in shape between the Star Formation Rate Density (SFRD) and Black Hole Accretion Rate Density (BHARD) out to z$\sim$ 3. This apparent connection between BH growth and star formation is only established globally; while both trends peak at z$\sim$ 2, the amount of stellar and black hole mass assembly occurring within the same galaxies is unknown. Computing these trends for the same galaxies will mitigate the present sample mismatch and can be accomplished with an IR-selected sample; however, the approach relies on a robust …


Dissecting The Most Extreme Starburst Events In The Universe With Gravitational Lensing, Patrick S. Kamienski Apr 2023

Dissecting The Most Extreme Starburst Events In The Universe With Gravitational Lensing, Patrick S. Kamienski

Doctoral Dissertations

Three billions years after the Big Bang, the rate at which galaxies in the Universe were forming stars was at its peak. Colloquially known as Cosmic Noon, this epoch (redshift z ~ 2) is crucial to our understanding of how galaxies evolve with time. Dusty star-forming galaxies (DSFGs) offer important clues to such fueling and quenching of star formation. With extreme infrared luminosities (1012 − 1014 solar luminosities), their inferred star formation rates are 100−10000 solar masses per year. Yet, the physical mechanisms by which they fuel this short-lived maximal starburst phase remain poorly understood. With this dissertation, …