Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Initial mass function"”.
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Investigating the Low-Mass Stellar Initial Mass Function in Draco
We present new analysis of the low-mass stellar initial mass function ($\sim0.4-0.8M_\odot$) in the Local Group dwarf spheroidal galaxy, Draco. Using archival HST/ACS and WFC3 optical imaging, we construct deep color-magnitude (CMD) diagrams in 3 different felds at 3 different galactocentric radii …
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The Initial Mass Function of the Orion Nebula Cluster from Near-Infrared Photometry
… of 330 s. As a result of our survey, we provide 2MASS-calibrated astrometry and photometry for ~7000 sources in the ONC region. Analyzing our photometric sample, we derive the contamination-completeness corrected (J,J-H) CMDs of the ONC, canceling out the contribution from the contaminant …
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The Evolution of Planetary Nebula Nuclei
… models of Paczynski, Schonberner and Iben, the initial mass function derived by Miller and Scalo, and various assumptions concerning mass loss during post-main sequence evolution. The distribution is found to be insensitive both to the assumed range of main-sequence progenitor mass and to …
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An X-ray census of the youngest galactic star clusters
… insights into the distribution of stellar masses in the Galaxy, the so called Initial Mass Function. Additionally, these clusters are the engines by which material in the Universe is recycled through the evolution and destruction of massive stars which redistribute material throughout a …
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The evolution of isotoipc abundances from high-redshift to the local universe
… isotope patterns at high-redshift require an initial mass function biased towards massive stars (Muller et al. 2006); and third, to test extant chemical evolution models against new observations of titanium isotopes that suggest an anti-correlation between trace-to-dominant isotopes and …
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Optical spectroscopic studies of two star forming regions
… and Serpens molecular clouds are sites of low mass star formation. The goals of this study were to identify young stellar objects (YSOs) and estimate ages and masses in order to infer an initial mass function (IMF), investigate disk evolution, and determine the star-forming history. Optical …
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Initial Conditions and Collapse of Prestellar Cores
… the turbulent flow. This mechanism creates the initial conditions for the formation of stellar objects. Due to the stochastic nature of turbulent velocity fields every prestellar core is unique in its shape and internal dynamics. This pecularity in the initial conditions is transformed via the …
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Simulations of cosmic reionization
… of the model is examined. We show that massive stars formed in abundance because of the assumed top-heavy stellar initial mass function during starbursts in the Baugh et al. (2005) model, triggered by galaxy mergers, are the dominant source of ionizing photons. We show that the …
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The Andromeda Optical and Infrared Disk Survey
… substantial (0.3 dex) differences in stellar mass estimates despite a common use of the Chabrier (2003) initial mass function. Stellar mass estimated from the resolved stellar population is larger than any mass estimate from SED models or colour-M/L relations (CMLRs). There is also …
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Comprehensive analyses of massive binaries and implications on stellar evolution
… stellar winds, and supernova explosions, massive stars (Mini & 8 M☉) bear a tremendous impact on galactic evolution. It became clear in recent decades that the majority of massive stars reside in binary systems. This thesis sets as a goal to quantify the impact of binarity (i.e., the …
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Star Formation in OB Associations and Clusters
… at two levels: at microscopic level by the initial mass function (IMF), and at macroscopic level by space, time, and intensity. To understand how star formation proceeds across a region, all four parameters need to be examined. We used the resolved massive stars and young stellar objects …
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The evolution of dark and luminous structure in massive early-type galaxies
… strong lensing and dynamical probes of the mass of early-type galaxies (ETGs) in order to improve our understanding of their dark and luminous mass structure and evolution. Firstly, I demonstrate that the dark matter halo of our nearest brightest cluster galaxy (BCG), M87, is centrally cored …
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Fokker-Planck models and globular cluster evolution
… 6397. The first set of models studied includes a mass spectrum, a tidal boundary and allows for a central energy source from the formation, hardening and destruction of binaries formed in three-body interactions. These models are compared to star-count mass functions and surface density profiles …
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Galaxy Formation in the Lambda-Cold Dark Matter Cosmology
… Baugh et al (2005), which assumes a top-heavy initial mass function (IMF) in starbursts and superwind feedback, and Bower et al (2006), which incorporates AGN feedback with a standard IMF. I compare the luminosity function, colours, sizes and morphology distributions of present-day galaxies in …
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The formation of high-mass stars and stellar clusters in the extreme environment of the Central Molecular Zone
… to the local environmental conditions? How do massive and dense stellar clusters form, and how does this crowded environment influence the stars that form within it? How do the most massive stars form and is there an upper limit to the stellar initial mass function (IMF)? Answering questions …
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Present and early star formation : a study on rotational and thermal properties
… of magnetic fields. The distribution of stellar masses at birth (the initial mass function, IMF) is another aspect that any theory of star formation must explain. We focus on the influence of the thermodynamic properties of star-forming gas and address this issue by studying the effects of a …
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Chemodynamical Properties of Simulated Late-type Galaxies
… the role of feedback, metal diffusion, and initial mass function selection, on the resulting chemistry of a new grid of M33-like disc simulations. The emphasis of the analysis is upon the resulting age-metallicity relations and metallicity distribution functions (in particular, the extreme …
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Resolved stellar populations: watching galaxy evolution in real time
… throughout the galaxy and the evolution of the mass and metallicity distributions. The system that has been studied in this project is the nearby galaxy M33, located in the Local Group. The photometric data was taken in the Canada-France-Hawaii Telescope with the MegaPrime/MegaCam wide-field …