Now showing items 1-20 of 65

• Applications of High-Resolution Observations of Millimeter Wavelengths ﻿

(2015-12-17)
nterferometric observations at millimeter wavelengths provide a precious, detailed view of certain astrophysical objects. This thesis is composed of studies that both rely on and enable this technique to study the structure ...
• Black Hole Accretion Disks and Jets: Connecting Simulations and Theory ﻿

(2013-09-25)
In recent years, general relativistic magnetohydrodynamic (GRMHD) simulations have produced more realistic models for black hole disks and jets. However the complexity of the simulations has created a disconnect between ...
• The Bright Side of Black Holes: Radiation From Black Hole Accretion Disks ﻿

(2015-05-15)
An understanding of radiation is paramount for connecting observations of accretion disks with the theory of black holes. In this thesis, we explore via radiative transfer postprocessing calculations the observational ...
• Constraining the Evolution of Galaxies over the Interaction Sequence with Multiwavelength Observations and Simulations ﻿

(2013-10-18)
Interactions are crucial for galaxy formation and profoundly affect their evolution. However, our understanding of the impact of interactions on star formation and activity of the central supermassive black hole remains ...
• Core-collapse Supernova Progenitors in the Era of Untargeted Transient Searches ﻿

(2014-06-06)
Core-collapse supernovae (SNe) are the highly energetic explosions of massive stars (> 8 solar masses) that are pervasive in their influence throughout astrophysics. They are the phenomenon with primary responsibility for ...
• Cosmic Extremes: Probing Energetic Transients With Radio Observations ﻿

(2018-05-11)
With the advent of sensitive facilities like the Karl G. Jansky Very Large Array and planning well underway for vastly more powerful wide-field interferometers like the Square Kilometer Array, the study of radio astrophysical ...
• Counting Stars: Developing Probabilistic Cataloging for Crowded Fields ﻿

(2018-05-09)
The depth of next generation surveys poses a great data analysis challenge: these surveys will suffer from crowding, making their images difficult to deblend and catalog. Sources in crowded fields are extremely covariant ...
• Development and Application of Tools to Characterize Transiting Astrophysical Systems ﻿

(2014-06-06)
Since the discovery of the first exoplanets (planets outside our Solar System) more than 20 years ago, there has been an increasing need for photometric and spectroscopic models to characterize these systems. While imaging ...
• Discovery of Giant Gamma-ray Bubbles in the Milky Way ﻿

(2012-08-09)
Based on data from the Fermi Gamma-ray Space Telescope, we have discovered two gigantic gamma-ray emitting bubble structures in our Milky Way (known as the Fermi bubbles), extending $\sim 50$ degrees above and below the ...
• Distances, Masses, Radii, and Metallicities of the Small Stars in the Solar Neighborhood ﻿

(2016-05-16)
Data from the NASA Kepler spacecraft indicate that small planets are common around the smallest main sequence stars (M dwarfs). Rocky planets transiting M dwarfs will be the best targets for atmospheric characterization ...
• The Diversity and Versatility of Gamma-Ray Bursts ﻿

(2015-05-17)
Gamma-ray bursts (GRBs) are the most energetic explosions in the Universe, thus providing a unique laboratory for the study of extreme astrophysical processes. In parallel, their large luminosity makes GRBs a premier probe ...
• The Dynamics and Evolution of Supermassive Black Holes in Merging Galaxies ﻿

(2012-08-03)
This thesis is a theoretical study of supermassive black holes (SMBHs) in merging galaxies. We consider the dynamics that govern inspiralling SMBH pairs and gravitational-wave (GW) recoiling SMBHs, as well as the fueling ...
• The Evolution of Rotation and Magnetism in Small Stars Near the Sun ﻿

(2016-05-19)
Despite the prevalence of M dwarfs, the smallest and most common type of main sequence star, their sizes, compositions, and ages are not well-constrained. Empirical determination of these properties is important for gaining ...
• Exploring the Long-Term and Extreme Variability of Stars ﻿

(2012-08-23)
This thesis presents observational studies of long-term and extreme variability of stars with the Digital Access to a Sky Century@Harvard (DASCH) project. Stellar variations over decades are poorly explored. With the unique ...
• 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 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 ...