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Showing 1 to 20 of 278 for “"star formation"”.
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Star formation in unobscured quasars
… all galaxy assembly occurs in intense bursts of star formation and black hole accretion, but the role of these two modes and how much they affect one another remains unclear. We thus investigate this in three complementary studies. In the first, we assemble a sample of 513 quasars identified by …
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Star formation and environment of galaxies
Across cosmic time, stars have contributed most of the radiant energy found in the Universe and have created nearly all the chemical elements heavier than helium. Understanding the evolution of the Universe requires understanding the history of star formation. Stars form in galaxies, which are in …
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Massive Star Formation at High Spatial Resolution
This thesis studies the early phases of massive stars and their impact on the surrounding. The capabilities of continuum radiative transfer (RT) codes to interpret the observations are also investigated. The main results of this work are: 1) Two massive star-forming regions are observed in the …
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Star Formation in OB Associations and Clusters
Star formation can be characterized 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 …
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The Nonisothermal Stage of Magnetic Star Formation
We follow the formation and subsequent evolution of fragments (or cores) in magnetically-supported, self-gravitating molecular clouds in two spatial dimensions. The six-fluid (neutrals, electrons, molecular and atomic ions, positively-charged, negatively-charged, and neutral grains) physical system …
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The magnetic decoupling stage of star formation
Submitted by Jesse Garrison (jagarris@illinois.edu) on 2012-05-05T20:06:25Z No. of bitstreams: 1 1998_desch.pdf: 7082777 bytes, checksum: acd91037c2f704067e52a9a7c65b7c73 (MD5)
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Exploring star formation in dwarf galaxies at Z1
… presents the first H α 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 …
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Star formation and disk stability in nearby galaxies
Observations of apparent cutoffs in star formation in the disks of galaxies as well as apparent thresholds in empirical laws of star formation have led many workers in the field to seek out the drivers and regulators of star formation in galaxies. Although the intricate details of these drivers are …
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The star formation and dynamics of nearby galaxies
A scaling relation between the surface density of star formation and gas in the disks of galaxies has become the basis of our understanding of extragalactic star formation on scales of hundreds of parsecs and larger. This is an empirical law but star formation is a complex process - the presence of …
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Star formation in the bars of nearby galaxies
Aims: In this study, we quantify the star formation activity in bars as a function of the host stellar mass and the morphological type. We use a sample of 70 barred spiral galaxies in the nearby universe taken from the Spitzer Survey of Stellar Structure in Galaxies (S⁴G). The data are combined …
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Shock formation and star formation in galactic spirals,
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1969.
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Understanding the Earliest Stages of High-mass Star Formation
High-mass star formation, contrary to its low-mass counterpart, remains poorly understood. This project aims to constrain the mechanisms driving the formation of OB stars and their precursors with the analysis of two main fields: Aquila, observed by the Balloon-borne Large-Aperture Submillimeter …
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Molecular clouds and star formation in the Inner Galaxy
A detailed understanding of the process of star formation is crucial for modern astrophysics. Stars form from the gravitational collapse of molecular gas clouds; it is the process by which cold molecular gas is transformed into the stars and planets that make up the many billions of galaxies in the …
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Evolution of Galaxies - Star Formation Histories in Nearby Spheroids
This thesis is about an investigation into the formation of spheroidal type galaxies. The investigation began with modelling studies of early-type galaxies and spiral bulges (SBs). From galaxy formation modelling studies led by experiments with a sample galaxy, some results were obtained; nonsolar …
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Modelling the star formation histories of nearby elliptical galaxies
… in the literature purporting to give the star formation history of a galaxy, or group of galaxies, where this is deduced from Lick observations taken from a single instrument, without separate verification from at least one other source. Within these limitations, this thesis also …
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Detecting episodes of star formation using Bayesian model selection.
… its use in detecting multiple episodes of star formation from the analysis of the Spectral Energy Distribution (SED) of galaxies. This method is validated by simulating galaxy catalogs modeled after 3D-HST galaxies at redshift z ∼ 1. The SED of galaxies are derived using multivariate kernel …
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Interstellar medium properties and star formation in nearby galaxies
… as a function of radius, column density, and star formation rate surface density. The super profiles can be described as the sum of a narrow and a broad Gaussian components. We associate the narrow component with the cold HI phase of the ISM and the broad component with the warm HI phase of …
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