Browsing FAS Theses and Dissertations by FAS Department "Astronomy"
Now showing items 21-40 of 77
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Formation of Supermassive Black Hole Seeds in the First Galaxies
(2018-05-10)Frontier observations of quasars at redshifts z > 6 suggest the existence of supermassive black holes of masses 1,000,000,000 solar masses when the Universe was less than a billion years old. These objects most likely grew ... -
From Astronomy to Chemistry: Origins of the Building Blocks of Life
(2020-05-04)The circumstances surrounding the origins of life on Earth are still unknown, though substantial progress has been made recently. In general, the origins of life might have followed the path where first, simple feedstock ... -
From Design to Detection: Joint Gravitational Wave and Electromagnetic Astronomy
(2018-05-11)The direct detection of gravitational waves from the inspiral and merger of compact object binaries by the Advanced LIGO and Virgo interferometers has ushered in an exciting new era of astronomy. Analysis of this gravitational ... -
From Stars to Galaxies: Unveiling Their Properties, Connection, and Evolution With Next Generation Stellar Models
(2018-05-11)Many areas of astrophysics spanning orders of magnitudes in physical scales—from exoplanets to high-redshift galaxies—are deeply rooted in our interpretation of light emitted by stars. Thus the importance of a well-tested ... -
Fueling Galaxy Growth Through Gas Accretion in Cosmological Simulations
(2015-05-17)Despite significant advances in the numerical modeling of galaxy formation and evolution, it is clear that a satisfactory theoretical picture of how galaxies acquire their baryons across cosmic time remains elusive. In ... -
The Fundamental Properties of Young Stars
(2016-05-18)Accurate knowledge of the fundamental properties of stars--mass, temperature, and luminosity--is key to our understanding of stellar evolution. In particular, empirical measurements of stellar mass are difficult to make ... -
Galactic Conformity via Small-Scale Clustering in Simulations and Surveys
(2016-05-14)Data from recent galaxy surveys reveal that, even at fixed stellar mass, quiescent galaxies are preferentially found around other red galaxies, an observation referred to as galactic conformity. This detection may offer ... -
Galaxy Mergers and Some Consequences: The Cosmological Context
(2016-05-18)The last few years have seen enormous progress in the field of galaxy formation and evolution. The latest generation of hydrodynamic cosmological simulations (e.g., the "Illustris" simulation) has been able to produce ... -
How I Learned to Stop Worrying and Love Eclipsing Binaries
(2015-09-01)Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational ... -
Hues of Habitability: Characterizing Pale Blue Dots Around Other Stars
(2015-05-16)A wide range of potentially rocky transiting planets in the habitable zone (HZ) have been detected by Kepler as well as ground-based searches. The spectral type of the host star will influence our ability to detect atmospheric ... -
In Pursuit of New Worlds: Searches for and Studies of Transiting Exoplanets from Three Space-Based Observatories
(2012-07-23)This thesis presents studies of transiting exoplanets using observations gathered in large part from space, with the NASA EPOXI Mission, the Spitzer Space Telescope, and the Kepler Mission. The first part of this thesis ... -
Infrared Light Curves of Type Ia Supernovae
(2012-09-12)This thesis presents the CfAIR2 data set, which includes over 4000 near-Infrared (NIR) \(JHK_s\)-band measurements of 104 Type Ia Supernovae (SN Ia) observed from 2005-2011 using PAIRITEL, the 1.3-m Peters Automated InfraRed ... -
Instability-Driven Limits on Ion Temperature Anisotropy in the Solar Wind: Observations and Linear Vlasov Theory
(2012-09-12)Kinetic microinstabilities in the solar wind arise when its non-thermal properties become too extreme. This thesis project focused specifically on the four instabilities associated with ion temperature anisotropy: the ... -
Interior Structure and Chemistry of Solid Exoplanets
(2015-05-08)Understanding the interior structures and chemistry of Earth-like exoplanets is crucial for us to characterize exoplanets, and to find potentially habitable planets. First, I provide a model grid of the mass-radius ... -
Long-Term Dynamics of High Mass Ratio Multiples
(2015-05-15)This thesis presents a series of studies on the dynamics of high mass ratio multiples, with applications to planetary systems orbiting stars and stellar systems orbiting supermassive black holes (SMBHs). Almost two ... -
Magnetic Fields in the Milky Way and the Magellanic Clouds
(2013-02-25)This thesis is an observational investigation into the origin of large-scale coherent magnetic fields in the Milky Way and the Magellanic Clouds. I use Faraday rotation measure of both polarized extragalactic sources and ... -
Magnetic Influences on the Solar Wind
(2016-05-12)The steady, supersonic outflow from the Sun we call the solar wind was first posited in the 1950s and initial theories rightly linked the acceleration of the wind to the existence of the million-degree solar corona. Still ... -
Mapping Milky Way Dust in 3D With Stellar Photometry
(2016-05-18)I present a three-dimensional map of interstellar dust reddening, covering three-quarters of the sky out to a distance of several kiloparsecs, based on Pan-STARRS 1 and 2MASS photometry. The map reveals a wealth of detailed ... -
Mapping the Milky Way in the Age of Gaia
(2020-05-15)A central problem in astronomy is converting the 2-D positions of sources observed on the sky to their 3-D positions in space. This has become especially important in the last decades as large-scale surveys such as Gaia ... -
Massive Black-Hole Binary Mergers: Dynamics, Environments & Expected Detections
(2018-05-13)This thesis studies the populations and dynamics of massive black-hole binaries and their mergers, and explores the implications for electromagnetic and gravitational-wave signals that will be detected in the near future. ...