Physical Sciences and Mathematics Commons^™

Mapping Galactic Acceleration With Pulsar Timing, Abigail Moran

University Scholar Projects

We have conducted a cross match of objects in Gaia Early Data Release 3 and millisecond pulsars (MSPs) in the International Pulsar Timing Array’s Data Release 2 (IPTA DR2) to identify binary systems. Gaia has parallax measurements for these optical companions, which we combine with pulsar timing based parallax measurements to calculate new combined MSP distances. Through this crossmatch with IPTA DR2 we improved five distance measurements and found the first parallax measurement for one MSP.

Using this Gaia crossmatch method now with a well-timed subset of the Australia Telescope National Facility’s database, we found three new pulsar distances. We …

Optimization Of Orbital Trajectories Using Neuroevolution Of Augmenting Topologies, Nathan Wetherell

University Scholar Projects

This project aims to determine the feasibility of using NeuroEvolution of Augmenting Topologies (NEAT), an advanced neural network evolution scheme, to optimize orbital transfer trajectories. More specifically, this project compares a genetically evolved neural network to a standard Hohmann transfer between Earth and Mars. To test these two methods, an N-body simulation environment was created to accurately determine the result of gravitational interactions on a theoretical spacecraft when combined with planned engine burns. Once created, this simulation environment was used to train the neural networks created using the NEAT Python module. A genetic algorithm was used to modify the topology …

Electromagnetic Detectability Of Binary Supermassive Black Holes, Kaylee Grace

Honors Scholar Theses

Supermassive black hole (SMBH) binaries can be produced by galaxy mergers and are important sources of gravitational waves. Although several binary candidates have been identified in previous work, none have yet been fully confirmed. These pairs are difficult to detect, since single accreting SMBHs can have pseudo-periodic lightcurves due to stochastic noise that can mimic the signature of binary SMBHs. The aforementioned lightcurves are the detections we classify as ”false-positive.” The Vera Rubin Observatory (VRO) will be a powerful new tool for detecting binary SMBHs. We determine the false-positive binary detection rate for VRO by attempting to recover sinusoidal binary …

The Sdss-Rm Project: Uv/Optical Accretion Disk Measurements For Supermassive Black Holes With Hubble Space Telescope, Megan Sturm

University Scholar Projects

We report accretion-disk structure measurements for eight rapidly accreting supermassive black holes selected from the Sloan Digital Sky Survey Reverberation Mapping project sample. Reverberation mapping uses light echoes to measure disk size from the time lag between variability in the inner/hotter and outer/cooler disk emission. We use Hubble Space Telescope ultraviolet observations coordinated with optical monitoring from the Liverpool Telescope and Las Cumbres Observatory. We find ten significant UV/optical lags for five out of the eight total targets. Through these time lags, we study the accretion disk as a function of disk size, temperature profile and radiative efficiency. We find …

Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen

Honors Scholar Theses

The advent of General Relativity via Einstein's field equations revolutionized our understanding of gravity in our solar system and universe. The idea of General Relativity posits that gravity is entirely due to the geometry of the universe -- that is, the mass distribution throughout the universe results in the ``curving" of spacetime, which gives us the physics we see on a large scale. In the framework of General Relativity, we find that the universe behaves differently than was predicted in the model of gravitation developed by Newton. We will derive the general relativistic model for a simple system near a …

The Geometry Of Spacetime And Its Singular Nature, Filip Dul

Honors Scholar Theses

One hundred years ago, Albert Einstein revolutionized our understanding of gravity, and thus the large-scale structure of spacetime, by implementing differential geometry as the pri- mary medium of its description, thereby condensing the relationship between mass, energy and curvature of spacetime manifolds with the Einstein field equations (EFE), the primary compo- nent of his theory of General Relativity. In this paper, we use the language of Semi-Riemannian Geometry to examine the Schwarzschild and the Friedmann-Lemaˆıtre-Robertson-Walker met- rics, which represent some of the most well-known solutions to the EFE. Our investigation of these metrics will lead us to the problem of …

Schwarzschild Spacetime And Friedmann-Lemaitre-Robertson-Walker Cosmology, Zachary Cohen

Honors Scholar Theses

The advent of General Relativity via Einstein's field equations revolutionized our understanding of gravity in our solar system and universe. The idea of General Relativity posits that gravity is entirely due to the geometry of the universe -- that is, the mass distribution throughout the universe results in the "curving" of spacetime, which gives us the physics we see on a large scale. In the framework of General Relativity, we find that the universe behaves differently than was predicted in the model of gravitation developed by Newton. We will derive the general relativistic model for a simple system near a …

Monte Carlo Simulations Of Atmospheric Loss By Stellar Winds From Exoplanets, Daniel P. Violette

University Scholar Projects

Hot Jupiters are a class of extra-solar planets. Massive gas giants on the same size scale as Jupiter, they orbit their host stars closely. This proximity results in large stellar winds capable of stripping away a planet’s atmosphere. Developing a more complete understanding of atmospheric mass loss and evolution in planetary bodies is critical, and Hot Jupiter systems are accessible analogues.

This project will seek to create a computational model capable of estimating mass loss rates due to stellar winds. A Monte Carlo method is utilized to take an ensemble of single, high-energy energetic neutral particles, produced by kilo-electronvolt stellar …

Monte Carlo Simulations Of Atmospheric Loss By Stellar Winds From Exoplanets, Daniel Violette

Honors Scholar Theses

Hot Jupiters are a class of extra-solar planets. Massive gas giants on the same size scale as Jupiter, they orbit their host stars closely. This proximity results in large stellar winds capable of stripping away a planet’s atmosphere. Developing a more complete understanding of atmospheric mass loss and evolution in planetary bodies is critical, and Hot Jupiter systems are accessible analogues.

This project will seek to create a computational model capable of estimating mass loss rates due to stellar winds. A Monte Carlo method is utilized to take an ensemble of single, high-energy energetic neutral particles, produced by kilo-electronvolt stellar …