Cosmology, Relativity, and Gravity Commons^™

Population Properties Of Compact Objects From The Second Ligo-Virgo Gravitational-Wave Transient Catalog, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, A. Adams, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, Tiffany Z. Summerscales

Faculty Publications

We report on the population of 47 compact binary mergers detected with a false-alarm rate of (BBH) population not discernible until now. First, the primary mass spectrum contains structure beyond a power law with a sharp high-mass cutoff; it is more consistent with a broken power law with a break at 39.7-+9.120.3 M? or a power law with a Gaussian feature peaking at 33.1-+5.64.0 M? (90% credible interval). While the primary mass distribution must extend to ~65 M? or beyond, only 2.9-+1.73.5% of systems have primary masses greater than 45 M?. Second, we find that a fraction of BBH systems …

Laplace's Equation In Fractional-Dimension Spaces, Kyle Schoener, Gabriele Varieschi

Honors Thesis

The correct way to model gravity is a question in physics whose answer continues to elude our understanding. One major difficulty is the dark matter problem, which exists due to the mass discrepancy between predicted and measured values in our universe. One possible solution to this problem is Modified Newtonian Dynamics (MOND). MOND is an alternative gravity model that modifies Newtonian Dynamics with the hope to avoid the necessity of dark matter.

Dr. Varieschi has done work connecting MOND to Newtonian Fractional-Dimension Gravity—the application of fractional calculus and fractional mechanics to classical gravitation laws. In this formulation, we can consider …

Aztlán Del Sol, Marcus Zúñiga

Chamisa: A Journal of Literary, Performance, and Visual Arts of the Greater Southwest

An artistic writing developed from the themes and concepts of an of art installation made by a visual artist of Mexican-American descent from New Mexico. The work references the relationship of Aztec mythology to the American Southwest, art theoretical discourse in object oriented ontology and aesthetics, and key ideas in astronomy. Additionally interwoven is an expanded sense for interpreting ancestry and history under the constructs of multicultural conceptions of time, specifically cultures with notable spiritual rituals of Sun worship and observation.

Systematical Uncertainties In The Measurement Of A Gamma-Ray Burst’S Isotropic Equivalent Energy, Kimberly Zoldak

Graduate Theses and Dissertations

Gamma-ray Bursts (GRBs) are the most energetic and luminous explosions in the Universe since the Big Bang, enabling them to be observed out to extremely large redshifts (z~9). Consequently, this makes them a promising cosmological standard candle candidate. Unfortunately, however, they have proven to be quite challenging to standardize. The GRB community has worked tirelessly at this task, and to date, has put forth several luminosity-distance relations, some more propitious than others. The most prevailing problem with these relations is in their sizable amount of scatter, likely due to measurement inconsistencies and errors in the variables they employ. This arises …

Distant Stars Become Future Homes: The Close Relationship Of Interstellar Between Hard Science-Fiction And Spectacle, Gabriel Davis

Undergraduate Honors Theses

Hard Science-fiction shares a close relationship with the element of spectacle. This is especially apparent in Christopher Nolan’s Interstellar (2014), a film based in realistic science and emotional appeal. Nolan makes use of creating a team comprised of creative minds with different backgrounds. This includes theoretical physicist Kip Thorne, co-writer Jonathan Nolan, and composer Hans Zimmer. Together, the four develop a film that focuses on three main facets of science: time dilation, black holes, and dimensions. Incorporating these elements based in the historical world gives Interstellar its classification as hard science-fiction, a genre based more solidly in realistic science than …

Experimental Constraint On Axionlike Particles Over Seven Orders Of Magnitude In Mass, Tanya S. Roussy, Daniel A. Palken, William B. Cairncross, Benjamin M. Brubaker, Daniel N. Gresh, Matt Grau, Kevin C. Cossel, Kia Boon Ng, Yuval Shagam, Yan Zhou, Victor V. Flambaum, Konrad W. Lehnert, Jun Ye, Eric A. Cornell

Physics & Astronomy Faculty Research

We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the HfF+ EDM oscillates in time due to interactions with candidate dark matter axionlike particles (ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range 10-22-10-15 eV. This is the first laboratory constraint on the ALP-gluon coupling …

029— Calculating Gravitational Waves In A Black Hole Binary System, Nami Nishimura

GREAT Day Posters

Our ultimate goal is to compute the gravitational waves in an extreme mass-ratio binary system. Since gravitational perturbations are difficult to calculate, we model the compact object as a point carrying a scalar charge q and moving around a spinning black holes.

In this project, we take advantage of symmetry under rotation around the spin axis in order to separate φ variables and leverage the periodicity of the source to separate t variable with a Fourier series. The remaining differential equations will be solved numerically with an appropriate discretization considering a grid of points in r-θ plane

Phenomenology Of Fermion Production During Axion Inflation, Michael Roberts

Doctoral Dissertations

We study the production of fermions through a derivative coupling to an axion inflaton and the effects of the produced fermions on the scalar and tensor metric perturbations. We show how such a coupling can arise naturally from supergravity with an axion-like field driving large-field inflation and small instanton-like corrections. We present analytic results for the scalar and tensor power spectra, and estimate the amplitude of the non-Gaussianties in the equilateral regime. The scalar spectrum is found to have a red-tilted spectral index, small non-Gaussianities, and can be dominant over the vacuum contribution. In contrast, the tensor power spectrum from …

Formation Of Supermassive Black Holes In The Early Universe, Arpan Das

Electronic Thesis and Dissertation Repository

The aim of the work presented in this thesis is to understand the formation and growth of the seeds of the supermassive black holes in early universe. Supermassive black holes (SMBH) with masses larger than 10⁸M_Sun have been observed when the Universe was only 800 Myr old. The formation and accretion history of the seeds of these supermassive black holes are a matter of debate. We consider the scenario of massive seed black hole formation which allows gas to directly collapse into a black hole (DCBH) of similar mass. Considering this scenario, we show that the mass …

Redefining Nietzsche’S Greatest Weight Into Contemporary Cosmology, Christian E. Coffinet-Crean

Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal

Friedrich Nietzsche’s theory of eternal recurrence and it’s cosmological value has been discredited and cast aside because of the lack of scientific backing the original theory had. In this essay, Nietzche’s eternal recurrence will be observed and analyzed through some of his major works and defended from outside criticism. Furthermore, Roger Penrose’s Conformal Cyclic Cosmology and Jean-Paul Luminet’s research are used in support for eternal recurrence as a cosmological theory. Luminet’s research of cosmic background radiation concludes that the universe has an odd but finite shape. Penrose’s research theorizes a sort of repeating universe, allowing time to be treated as …

Concentrated Lunar Resources: Imminent Implications For Governance And Justice, Martin Elvis, Alanna Krolikowski, Tony Milligan

History and Political Science Faculty Research & Creative Works

Numerous missions planned for the next decade are likely to target a handful of small sites of interest on the Moon's surface, creating risks of crowding and interference at these locations. The Moon presents finite and scarce areas with rare topography or concentrations of resources of special value. Locations of interest to science, notably for astronomy, include the Peaks of Eternal Light, the coldest of the cold traps and smooth areas on the far side. Regions richest in physical resources could also be uniquely suited to settlement and commerce. Such sites of interest are both few and small. Typically, there …

Critical Phenomena In The Gravitational Collapse Of Electromagnetic Dipole And Quadrupole Waves, Maria F. Perez Mendoza

Honors Projects

We report on critical phenomena in the gravitational collapse of electromagnetic waves. Generalizing earlier results that focused on dipole electromagnetic waves, we here compare with quadrupole waves in axisymmetry. We perform numerical simulations of dipole and quadrupole wave initial data, fine-tuning both sets of data to the onset of black hole formation in order to study the critical solution and related critical phenomena. We observe that different multipole moments have different symmetries, indicating that the critical solution for electromagnetic waves cannot be unique, at least not globally. This is confirmed in our numerical simulations: while dipole data lead to a …

Using Numerical Relativity To Explore Strong Gravity And Develop Force-Free Electrodynamics Simulation Software With Best-Practice Development, Patrick E. Nelson

Graduate Theses, Dissertations, and Problem Reports

In this dissertation, we explore the effects of extremely strong gravitational and electro- dynamic fields using the techniques of numerical relativity. We use the existing black hole simulation software in the Einstein Toolkit to compute the spin-up of two initially nonspin- ning black holes as they pass by each other in space. The angular momentum is imparted by the tidal interaction between the two black holes, in a parallel to Earth’s tides, as described by classical mechanics, which also transfer angular momentum between the Earth’s rotation and the Moon’s orbit. The largest observed dimensionless spin observed was 0.20 with an …

Cosmological Gravitational Waves: Refining A General Rule Of Thumb For Reheating, David Zhou

Honors Projects

There are predictions for cosmological gravitational wave backgrounds from reheating based on various models. But, these predictions do not address the question of how an observed spectrum relates back to an unknown model or parameter. Given this problem, we have numerically and analytically investigated a variety of chaotic inflation models and their gravitational wave spectra. In doing so, we found a power law relation between gravitational wave peak frequency and an underlying chaotic inflation parameter. We found a two-class amplitude puzzle related to how strongly a matter producing field is coupled to the inflaton. We estimated the parameter describing how …

Development Of Eccentric Black Hole Binary Searches In The Ligo And Pta Regimes, Belinda D. Cheeseboro

Graduate Theses, Dissertations, and Problem Reports

In the past several years, a plethora of gravitational wave events have been detected leading to better understanding of binary black holes, binary neutron stars, and neutron star black hole binaries. All of these transient detections have helped us better understand the dynamics of these systems as well as the populations of these objects, but each of these sources was detected with models that neglected eccentricity. Eccentricity is one of several potential markers for determining the formation of binary systems. Detecting gravitational waves from eccentric sources can better our understanding of such systems and help constrain theories about their formation. …

Monitoring Agns With H-Beta Asymmetry: Markarian 841, Samuel J. Schonsberg

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Quasars are among the most luminous objects in the Universe, and the mechanism behind their luminosity was shrouded in mystery decades after their discovery. Since then, we have found that these objects are active galactic nuclei (AGN), which are powered by actively-feeding super massive black holes at the center of a galaxy. But we still know fairly little about the structure and motion of the material surrounding active super massive black holes, and most of these objects are not resolvable by conventional observations. We use a technique called reverberation mapping, which is traditionally used only as a mass determination …

The Causal Topology Of Neutral 4-Manifolds With Null Boundary, Nikos Georgiou, Brendan Guilfoyle

Publications

This paper considers aspects of 4-manifold topology from the point of view of the null cone of a neutral metric, a point of view we call neutral causal topology. In particular, we construct and investigate neutral 4-manifolds with null boundaries that arise from canonical 3- and 4-dimensional settings. A null hypersurface is foliated by its normal and, in the neutral case, inherits a pair of totally null planes at each point. This paper focuses on these plane bundles in a number of classical settings The first construction is the conformal compactification of flat neutral 4- space into the 4-ball. The …

Tidal Locking And The Gravitational Fold Catastrophe, Andrea Ferroglia, Miguel C. N. Fiolhais

Publications and Research

The purpose of this work is to study the phenomenon of tidal locking in a pedagogical framework by analyzing the effective gravitational potential of a two-body system with two spinning objects. It is shown that the effective potential of such a system is an example of a fold catastrophe. In fact, the existence of a local minimum and saddle point, corresponding to tidally locked circular orbits, is regulated by a single dimensionless control parameter that depends on the properties of the two bodies and on the total angular momentum of the system. The method described in this work results in …

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …

Mars 2020: A Step Closer To The Red Planet, Kevin Ng, Matthew Khargie, Omadevi Singh, Sashi Singh, Nazrul I. Khandaker, Rajendra Persaud

Publications and Research

This research paper primarily focuses on the NASA Mars 2020 mission, but will also revisit and discuss past rover missions. As the Mars 2020 mission is ongoing, some information will be updated accordingly. For decades, humans have dreamed of the colonization of Mars for many reasons, such as some similarities shared by Earth and Mars or the close proximity to our planet. In fact, dozens of films, books, and articles have been written, especially in the past 2 decades, about the possibility. As technology advances, we develop newer equipment to hopefully make this possibility into a reality. Of course, placing …

Microgravity And Its Bearing With Space Flight-Related Research, Farhan Tanvir, Nazrul I. Khandaker, Rajendra Persaud, Jeff Guan

Publications and Research

This study investigates the unique properties and applications of microgravity in the context of spaceflight research. Understanding and harnessing the behaviors of a microgravity environment opens up the doors to long-term space travel and consequently, future missions to other planets within our solar system. More specifically, simulating and conducting experiments in microgravity environments helps us explore its effects on the various necessary tasks and behaviors that are carried out during spaceflight. The most immediate and pronounced effects of microgravity are on human physiology. In particular, studies have shown that prolonged exposure to microgravity can result in a 20% decrease in …

Human Health And Wellness In Space: A Review Of Common Effects, Current Research, And Methods Of Prevention, Sonnet Xu, Rajendra Persaud, Nazrul I. Khandaker, Jasmin Budhan

Publications and Research

Space poses a threat to space crew wellness, where microgravity, isolation, radiation, and other conditions exert strain on human health. This study explores the changes to the human body in space and how it contributes to major threats to health during spaceflights. The effects of the hostile environment of outer space are all examined here, along with resultant changes to behavior, physiology, and the difficulty of remote diagnosis for health treatment in space. This review also considers the implications to the human cartilage, brain, and eyes along with the various other hazards and physiological alterations.

Human health in space is …

Binary Neutron Star Mergers: Testing Ejecta Models For High Mass-Ratios, Allen Murray

The Journal of Purdue Undergraduate Research

Neutron stars are extremely dense stellar corpses which sometimes exist in orbiting pairs known as binary neutron star (BNS) systems. The mass ratio (q) of a BNS system is defined as the mass of the heavier neutron star divided by the mass of the lighter neutron star. Over time the neutron stars will inspiral toward one another and produce a merger event. Although rare, these events can be rich sources of observational data due to their many electromagnetic emissions as well as the gravitational waves they produce. The ability to extract physical information from such observations relies heavily on numerical …

Cosmological Initial Data For Numerical Relativity, David Garfinkle, Lawrence Mead

Faculty Publications

© 2020 American Physical Society. We find initial data for numerical relativity simulations of inhomogeneous cosmologies. This involves treating an exceptional case of the general relativity constraint equations. We devise analytic and numerical methods to treat this exceptional case. We apply the analytic method to the standard case of cosmology with a single scalar field. The numerical method is applied to the two-field ekpyrotic cosmology.

Topics In Gravitational Wave Physics, Aaron David Johnson

Graduate Theses and Dissertations

We begin with a brief introduction to gravitational waves. Next we look into the origin of the Chandrasekhar transformations between the different equations found by perturbing a Schwarzschild black hole. Some of the relationships turn out to be Darboux transformations. Then we turn to GW150914, the first detected black hole binary system, to see if the nonlinear memory might be detectable by current and future detectors. Finally, we develop an updated code for computing equatorial extreme mass ratio inspirals which will be open sourced as soon as it has been generalized for arbitrary inclinations.

Spherically Symmetric Charged Anisotropic Solution In Higher Dimensional Bimetric General Relativity, D. N. Pandya, A. H. Hasmani

Applications and Applied Mathematics: An International Journal (AAM)

In this paper we have obtained a solution of field equations of Rosen’s bimetric general relativity (BGR) for the static spherically symmetric space-time with charged anisotropic fluid distribution in (n+2)-dimensions. An exact solution is obtained and a special case is considered. This work is an extension of our previous work where four-dimensional case was discussed.

Stability Of Regular Thin Shell Wormholes Supported By Vdw Quintessence, A. Eid

Applications and Applied Mathematics: An International Journal (AAM)

The dynamical equations of motion for a thin shell wormhole from regular black holes that are supported by Van der Waals (VDW) quintessence equation of state (EoS) are constructed, through cut and -paste technique. The linearized stability of regular wormhole is derived. The presences of unstable and stable static solutions with different value of some parameters are analyzed.

A Mildly Relativistic Outflow From The Energentic, Fast-Rising Blue Optical Transient Css161010 In A Dwarf Galaxy, Deanne L. Coppejans, R. Margutti, G. Terreran, A. J. Nayana, E. R. Coughlin, T. Laskar, K. D. Alexander, M. Bietenholz, D. Caprioli, P. Chandra, M. R. Drout, D. Frederiks, C. Frohmaier, K. H. Hurley, C. S. Kochanek, M. Macleod, A. Meisner, P. E. Nugent, A. Ridnaia, D. J. Sand, D. Svinkin, C. Ward, S. Yang, A. Baldeschi, I. V. Chilingarian, Y. Dong, C. Esquivia, W. Fong, C. Guidorzi, P. Lundqvist, D. Milisavljevic

Physics & Astronomy Faculty Research

We present X-ray and radio observations of the Fast Blue Optical Transient CRTS-CSS161010 J045834−081803 (CSS161010 hereafter) at t = 69–531 days. CSS161010 shows luminous X-ray (L x ~ 5 × 1039 erg s−1) and radio (L ν ~ 1029 erg s−1 Hz−1) emission. The radio emission peaked at ~100 days post-transient explosion and rapidly decayed. We interpret these observations in the context of synchrotron emission from an expanding blast wave. CSS161010 launched a mildly relativistic outflow with velocity Γβc ≥ 0.55c at ~100 days. This is faster than the non-relativistic AT 2018cow (Γβc ~ 0.1c) and closer to ZTF18abvkwla (Γβc …

Swift Spectroscopy Of The Accretion Disk Wind In The Black Hole Gro J1655-40, M. Balakrishnan, J. M. Miller, N. Trueba, M. Reynolds, J. Raymond, Daniel Proga, A. C. Fabian, T. Kallman, J. Kaastra

Physics & Astronomy Faculty Research

Chandra obtained two High Energy Transmission Grating spectra of the stellar-mass black hole GRO J1655−40 during its 2005 outburst, revealing a rich and complex disk wind. Soon after its launch, the Neil Gehrels Swift Observatory began monitoring the same outburst. Some X-ray Telescope (XRT) observations were obtained in a mode that makes it impossible to remove strong Mn calibration lines, so the Fe Kα line region in the spectra was previously neglected. However, these lines enable a precise calibration of the energy scale, facilitating studies of the absorption-dominated disk wind and its velocity shifts. Here we present fits to 15 …

Automated Spectroscopic Detection And Mapping Using Alma And Machine Learningtechniques, Steven Cocke, Andrew Wilkins, Josephine Mcdaniel, John Santerre, Conor Nixon

SMU Data Science Review

In this paper we present a methodology for automating theclassification of spectrally resolved observations of multiple emissionlines with the Atacama Large Millimeter/submillimeter Array (ALMA).Molecules in planetary atmospheres emit or absorb different wavelengthsof light thereby providing a unique signature for each species. ALMAdata were taken from interferometric observations of Titan made be-tween UT 2012 July 03 23:22:14 and 2012 July 04 01:06:18 as part ofALMA project 2011.0.00319.S. We first employed a greedy set cover algorithm to identify the most probable molecules that would reproducethe set of frequencies with respective flux greater than 3σaway from themean. We then selected a subset of …