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 20 of 34 for “"Dwarf galaxies"”.
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Neutral Hydrogen in Local Group Dwarf Galaxies
The gas content of the faintest and lowest mass dwarf galaxies provide means to study the evolution of these unique objects. The evolutionary histories of low mass dwarf galaxies are interesting in their own right, but may also provide insight into fundamental cosmological problems. These include …
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HI survey of local group dwarf galaxies
This thesis investigates the HI properties of 3 dwarf irregular galaxies and one blue compact dwarf galaxy of the Local Group. The data set of each dwarf irregular galaxy was obtained with the Karoo Array Telescope (KAT-7) while the blue compact dwarf was observed with the Dominion Radio …
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Simulations of the Formation of Tidal Dwarf Galaxies
Wir praesentieren die Ergebisse von numerischen Simulationen der Gezeitenarme in wechselwirkenden Galaxien. Die Entstehung von Zwerggalaxien in diesen Gezeitenarmen wurde mit sehr hoher Aufloesung untersucht. Wir stellen fest, dass in reinen N-body Simulationen keine kollabierten Objekte in den …
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Exploring star formation in dwarf galaxies at Z1
… measurements of star formation rates (SFRs) for dwarf galaxies at z~1 (when the Universe was approximately half its current age) using the Hubble Space Telescope (HST).We target a sample derived from the Redshift One LDSS3 Emission Line Survey (ROLES), which used [OII]3727 as a tracer of star …
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Mapping the Ancient Milky Way and its Relic Dwarf Galaxies
… years after the Big Bang, the first stars and galaxies began transforming the dark, primitive universe into the rich, complex one that we observe today. These primitive objects thus govern crucial, foundational rungs in our understanding of how the universe came to be. However, little is …
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Dwarf Galaxies in a Cosmological Context: A Testbench for Galaxy Modeling
… code as an analog to local low-luminosity dwarf irregular and dwarf spheroidal galaxies. The primary goals of this study are to investigate the roles of reionization and supernova feedback in determining the star-formation histories of low-mass dwarf galaxies and to explore the effect of …
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Extreme Stellar Populations in the Universe: Backsplash Dwarf Galaxies and Wandering Stars
… that stars beyond the virial radii of galaxies may be generated by the gravitational impulse received by a satellite as it passes through the pericenter of its orbit around its parent. These stars may become energetically unbound (escaped stars), or may travel to further than a few …
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Black Hole Feedback in New Regimes: Modelling Dwarf Galaxies with Active Galactic Nuclei
… both isolated and cosmological simulations of dwarf galaxies. Firstly, I perform high-resolution simulations of isolated dwarf galaxies. In these simulations, the AGN has only a limited direct effect on star formation rates. There is, however, a significant effect on outflows, which are notably …
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Properties and Kinematics of the Interstellar Medium in a Small Sample of Nearby Dwarf Galaxies
The distribution and kinematics of HI in the dwarf ellipticals NGC 185 and NGC 205 are significantly different from those in giant ellipticals, so that an internal origin for the gas in the dwarf ellipticals should be considered. Finally, the presence of gas in LGS 3 conflicts with evolutionary …
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A multi-wavelength study of the dwarf galaxies NGC 2915 and NGC 1705 : star formation, gas dynamics and dark matter
… study of the nearby blue compact dwarf galaxies NGC 2915 and NGC 1705. The primary data set (nearly 100 hours of on-source data) for each galaxy consists of new observations of the neutral hydrogen (Hi) line obtained with the Australia Telescope Compact Array, October 2006 - May …
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The Legacy of the First Galaxies: Exploring Ancient Stars in the Milky Way
… years after the Big Bang, the first stars and galaxies transformed the Universe. These ancient systems launched the creation of every galaxy we see today, including the Milky Way. Ever since, for the last 13 billion years, the Milky Way has grown through galaxy mergers. Several of these mergers …
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Signatures of the first stars in relics of the first galaxies
… following the big bang, the first stars and galaxies fundamentally transformed the universe. They polluted the universe with the first heavy elements, and they produced high energy photons that reionized the intergalactic medium. Understanding this early era is at the frontier of modern …
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The role of obscured activity in galaxy formation
… I investigate the formation and evolution of the galaxies that eventually form the colour-magnitude relation (CMR) in local galaxy clusters. I survey galaxies that lie on the CMR in nine massive clusters at z~0.2, environments in which the build-up of the faint end of the CMR is still underway. I …
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Understanding the Milky Way with Stars
"How do galaxies form?" is one of the most important questions in modern astrophysics. Hierarchical growth, the most plausible theory behind galaxy formation, suggests that galaxies, including the Milky Way, assemble through the accretion of smaller systems, over a scaffolding of the invisible Dark …
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Probing local group galactic substructure with cosmological simulations
… only cosmological N-body simulations of MW-mass galaxies to address topics related to these issues. In light of the recent Planck mission, I investigate how changes to cosmological parameters affect dark matter halo substructure. I find that the process of continuous sub-halo accretion and …
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On the Ionization and Chemical Evolution of the Intergalactic Medium
… feedback from Population It stars formed in dwarf galaxies at redshifts z ≲ 10. We conclude that, the PopIII metals alone are insufficient to explain the detected levels of metal enrichment in the observable Universe. We find that at late redshifts a significant portion of the primordial …
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Chemodynamical Properties of Simulated Late-type Galaxies
The chemistry of galaxies provides a powerful probe of the underlying physics driving their evolution, complementing the traditional tools of morphology, kinematics,and colours. This dissertation examines several aspects of the galactic chemical evolution of late-type galaxies - both disc-like and …
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Ultra-diffuse galaxy candidatesin stripe 82 clusters
The evolution of galaxies in the cluster environment is a complex process, with many outstanding questions. A wide range of galaxy morphologies, colours, sizes and luminosities are found in clusters, the least studied of which are the faint galaxy populations. Studying the faint end of the galaxy …
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A tale of two particles
… damping, it was the CMB of light, it was the dwarf galaxy of darkness, it was the largest of cosmic scales, it was the smallest of Milky Way subhalos, we had multiple nonminimally coupled inflatons before us, we had inelastically selfinteracting dark matter before us, we were all going direct …
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