Astrophysics and Astronomy Commons^™

Formation Of Titan Aerosol From Co And Ch4, Tate Christensen

Honors Program Theses

In 1952 Stanley Miller and Harold Urey conducted an experiment that would simulate the conditions of early earth (Miller, 1953). The purpose was to observe the chemical origins of life, and the conclusion supported an earlier theory that such conditions favor the synthesis of more complex organic compounds from simpler inorganic molecules. The research conducted in Dr. Sebree’s lab is an extension of these early findings. It is believed that early Earth was composed mostly of nitrogen, carbon monoxide, carbon dioxide and methane as opposed to our atmosphere of nitrogen and oxygen today.

Saturn’s largest moon, Titan, has qualities relatively …

Search For Post-Merger Gravitational Waves From The Remnant Of The Binary Neutron Star Merger Gw170817, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

The first observation of a binary neutron star (NS) coalescence by the Advanced LIGO and Advanced Virgo gravitational-wave (GW) detectors offers an unprecedented opportunity to study matter under the most extreme conditions. After such a merger, a compact remnant is left over whose nature depends primarily on the masses of the inspiraling objects and on the equation of state of nuclear matter. This could be either a black hole (BH) or an NS, with the latter being either long-lived or too massive for stability implying delayed collapse to a BH. Here, we present a search for GWs from the remnant …

Using Hubble Parameter Measurements To Find Constraints On Dark Energy Based On Different Cosmological Models, William Wilson, Muhammad O. Farooq

Student Works

In this paper, Hubble parameter versus redshift data, collected from multiple resources, is used to place constraints on the parameters of two current Cosmological dark energy models. The first dark energy model considered is the Standard Model of cosmology, also known as ΛCDM with spatial curvature, which is primarily based on Einstein’s General Theory of Relativity with a spatially homogeneous time-independent cosmological constant, Λ. The second is the XCDM model which parameterize dark energy as a fluid whose density can vary with time. The H(z) data collected through different experimental sources was used to put constraints on the parameters of …

Using Student Characteristics, Student Spatial-Content Knowledge, And Teacher Spatial-Content Knowledge To Predict Student Spatial-Content Knowledge Of Lunar Phases, Kyle A. Curry

Theses and Dissertations--Science, Technology, Engineering, and Mathematics (STEM) Education

Student demographic characteristics of gender and race/ethnicity, students’ spatial-content knowledge as measured by pre-instructional performance on the Lunar Phases Concept Inventory (LPCI) (Lindell & Olsen), and post-instructional performance on the Purdue Visualization of Rotations Test (PSVT) (Bodner & Guay, 1997), and teachers’ spatial-content knowledge as measured by the two assessments were considered to predict students’ overall understanding of lunar phases as measured by post-instructional results on the LPCI. A mixed modeling approach was used in a hierarchal manner to evaluate the student learning outcomes. Results showed that student gender was not a significant predictor of post-instructional student performance, but students …

Ruo2 Ph Sensor With Super-Glue-Inspired Reference Electrode, Wade Lonsdale, Magdalena Wajrak, Kamal Alameh

Research outputs 2014 to 2021

A pH-sensitive RuO2 electrode coated in a commercial cyanoacrylate adhesive typically exhibits very low pH sensitivity, and could be paired with a RuO2 working electrode as a differential type pH sensor. However, such sensors display poor performance in real sample matrices. A pH sensor employing a RuO2 pH-sensitive working electrode and a SiO2-PVB junction-modified RuO2 reference electrode is developed as an alternative high-performance solution. This sensor exhibits a performance similar to that of a commercial glass pH sensor in some common sample matrices, particularly, an excellent pH sensitivity of 55.7 mV/pH, a hysteresis as low as 2.7 mV, and a …

First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig, S. M. Nossal, L. M. Haffner

Publications

A new, high-resolution field-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts.Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration times, …

Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Omer Farooq, Foram Ranjeet Madiyar, Sara Crandall, Bharat Ratra

Publications

We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 ≤ z ≤ 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, zda, from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H0. The weighted mean of our measurements is zda = 0.72±0.05 (0.84±0.03) for H0 = 68 ± …

The Remote Observatories Of The Southeastern Association For Research In Astronomy (Sara), William C. Keel, Terry D. Oswalt, Peter Mack, Gary Henson, Todd Hillwig, Et Al.

Publications

We describe the remote facilities operated by the Southeastern Association for Research in Astronomy (SARA) , a consortium of colleges and universities in the US partnered with Lowell Observatory, the Chilean National Telescope Allocation Committee, and the Instituto de Astrofísica de Canarias. SARA observatories comprise a 0.96 m telescope at Kitt Peak, Arizona; one of 0.6 m aperture on Cerro Tololo, Chile; and the 1 m Jacobus Kapteyn Telescope at the Roque de los Muchachos, La Palma, Spain. All are operated using standard VNC or Radmin protocols communicating with on-site PCs. Remote operation offers considerable flexibility in scheduling, allowing long-term …

Utilizing The O-C Method To Determine Third-Body Existence In Eclipsing Binary Systems, Patrice Majewski, Tomomi Otani, Terry D. Oswalt

Publications

Previous studies on the subject of eclipsing binaries (EBs) within the Kepler field have been adequately determined the period, distance, and other stellar parameters of these systems (Borkovits, et al. 2015). Additionally, with the use of Observed-minus-Calculated (O-C) plots, variation in the timing of timing of eclipses can be easily detected. The eclipse timing shifts may be caused by dynamical effects or by light-travel time effects (LTTE) caused by the existence of a third body. The following research was conducted on ten binaries within the Kepler “K2” Campaign 5 field whose light curves (LCs) showed evidence of eclipses with periods …

Joint Hierarchical Models For Sparsely Sampled High-Dimensional Lidar And Forest Variables, Andrew O. Finley, Sudipto Banerjee, Yuzhen Zhou, Bruce D. Cook, Chad Babcock

United States National Aeronautics and Space Administration: Publications

Recent advancements in remote sensing technology, specifically Light Detection and Ranging (LiDAR) sensors, provide the data needed to quantify forest characteristics at a fine spatial resolution over large geographic domains. From an inferential standpoint, there is interest in prediction and interpolation of the often sparsely sampled and spatially misaligned LiDAR signals and forest variables. We propose a fully process-based Bayesian hierarchical model for above ground biomass (AGB) and LiDAR signals. The processbased framework offers richness in inferential capabilities, e.g., inference on the entire underlying processes instead of estimates only at pre-specified points. Key challenges we obviate include misalignment between the …

Non-Hermiticity-Induced Flat Band, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

We demonstrate the emergence of an entire flat band with no complex component embedded in dispersive bands at the exceptional point of a PT -symmetric photonic lattice. For this to occur, the gain and loss parameter effectively alters the size of the partial flat band windows and band gap of the photonic lattice simultaneously. The mode associated with the entire flat band is robust against changes in the system size and survives even at the edge of the lattice. Our proposal offers a route for controllable localization of light in non-Hermitian systems and a technique for measuring non-Hermiticity via localization.

Series Solutions Of Polarized Gowdy Universes, Doniray Brusaferro

Theses and Dissertations

Einstein's field equations are a system of ten partial differential equations. For a special class of spacetimes known as Gowdy spacetimes, the number of equations is reduced due to additional structure of two dimensional isometry groups with mutually orthogonal Killing vectors. In this thesis, we focus on a particular model of Gowdy spacetimes known as the polarized T³ model, and provide an explicit solution to Einstein's equations.

Nonperturbative Evolution Of Parton Quasi-Distributions, A. V. Radyushkin

Physics Faculty Publications

Using the formalism of parton virtuality distribution functions (VDFs) we establish a connection between the transverse momentum dependent distributions (TMDs) F(x,k²_⊥) and quasi-distributions (PQDs) Q(y,p₃) introduced recently by X. Ji for lattice QCD extraction of parton distributions f(x). We build models for PQDs from the VDF-based models for soft TMDs, and analyze the p₃ dependence of the resulting PQDs. We observe a strong nonperturbative evolution of PQDs for small and moderately large values of p₃ reflecting the transverse momentum dependence of TMDs. Thus, the study of PQDs on the lattice …

A Quantitative Analysis Of The Fretted Terrain Valleys, Arabia Terra, Mars, Kelsey Anne Mason

Open Access Theses & Dissertations

Fretted terrain describes regions on Mars with low-lying, flat valleys separated by steep cliffs that often form polygonal-shaped mesas. The fretted terrain valleys have a morphology distinct from other valleys found on Mars, and their unknown origin may hold insights into critical questions about Mars' tectonic, magmatic, and hydrologic history. Current hypoThesis for the formation of the fretted terrain include fracturing as well as hydrological flow processes such as fluvial or glacial erosion. The region for this study is located in eastern Arabia Terra and is the type-location for fretted terrain. By qualitatively and quantitatively documenting the planform, or map-view, …

The Sluggs Survey: A Catalog Of Over 4000 Globular Cluster Radial Velocities In 27 Nearby Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee Spitler, Sabine Bellstedt, Nicola Pastorello, Alexa Villaume, Asher Wasserman, Vincenzo Pota

Faculty Publications

No abstract provided.

The Sluggs Survey: Revisiting The Correlation Between X-Ray Luminosity And Total Mass Of Massive Early-Type Galaxies, Duncan Forbes, Adebusola Alabi, Aaron Romanowsky, Dong-Woo Kim, Jean Brodie, Giuseppina Fabbiano

Faculty Publications

Here we utilize recent measures of galaxy total dynamical mass and X-ray gas luminosities (LX,Gas) for a sample of 29 massive early-type galaxies from the SLUGGS survey to probe LX, Gas–mass scaling relations. In particular, we investigate scalings with stellar mass, dynamical mass within 5 effective radii (Re) and total virial mass. We also compare these relations with predictions from Λ cold dark matter simulations. We find a strong linear relationship between LX, Gas and galaxy dynamical mass within 5Re, which is consistent with the recent cosmological simulations of Choi et al. that incorporate mechanical heating from AGN. We conclude …

Extensive Globular Cluster Systems Associated With Ultra Diffuse Galaxies In The Coma Cluster, Pieter Van Dokkum, Roberto Abraham, Aaron Romanowsky, Jean Brodie, Charlie Conroy, Shany Danieli, Deborah Lokhors, Allison Merritt, Lamiya Mowla, Jielai Zhang

Faculty Publications

We present Hubble Space Telescope (HST) imaging of two ultra diffuse galaxies (UDGs) with measured stellar velocity dispersions in the Coma cluster. The galaxies, Dragonfly 44 and DFX1, have effective radii of 4.7 kpc and 3.5 kpc and velocity dispersions of km s−1 and km s−1, respectively. Both galaxies are associated with a striking number of compact objects, tentatively identified as globular clusters: for Dragonfly 44 and for DFX1. The number of globular clusters is much higher than expected from the luminosities of the galaxies but is consistent with expectations from the empirical relation between dynamical mass and globular cluster …

Multispectral Observations And Analysis Of The Rosette Nebula, Jeremy Huber

Theses and Dissertations--Physics and Astronomy

The Rosette nebula is a large, ring-shaped emission nebula with a distinctive central cavity excavated by its central cluster of OB stars. Toward understanding the three dimensional structure and fundamental physical processes of this object, we have acquired flux-calibrated, 4-degree field, deep exposures of the Rosette region through 3 nm bandwidth H-alpha (656.3 nm) as well as H-beta (486.1nm), [OIII] (500.7 nm) and [SII] (671.6 nm) filters with 4.5 nm bandwidth. The 4 arcsec/pixel images are supplemented with 4 degree field slit spectra and combined with archival data from the Galactic Evolution Explorer satellite (GALEX), Akari, the Infrared Astronomical Satellite …

Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo

Doctoral Dissertations and Master's Theses

Vertical transport due to dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 s and 500 m, …

Determination Of Stellar Parameters Through The Use Of All Available Flux Data And Model Spectral Energy Distributions, Gemunu Ekanayake

Theses and Dissertations--Physics and Astronomy

Basic stellar atmospheric parameters, such as effective temperature, surface gravity, and metallicity plays a vital role in the characterization of various stellar populations in the Milky Way. The Stellar parameters can be measured by adopting one or more observational techniques, such as spectroscopy, photometry, interferometry, etc. Finding new and innovative ways to combine these observational data to derive reliable stellar parameters and to use them to characterize some of the stellar populations in our galaxy is the main goal of this thesis.

Our initial work, based on the spectroscopic and photometric data available in literature, had the objective of calibrating …

Mayo Dark Skies Park: A Virtual Experience, Mayo Dark Skies Community Group, Frank Prendergast

Datasets

The Mayo Dark Skies Community Group, in collaboration with the Dublin Institution of Technology, is pleased to launch a digital virtual experience of the Mayo Dark Sky Park. Following its designation as an International Dark Sky Park (Gold Tier), it is now possible to experience a part of this magnificent and pristine skyscape on your computer. This has been made possible using open source software (Stellarium http://www.stellarium.org/) and a specially commissioned digital panorama of the horizon surrounding the Ballycroy National Park Visitor Centre.

Stellarium is an open source planetarium for your computer and shows a fully realistic …

Glass Plate Slides On Astronomy, Zach S. Henderson Library Special Collections

Finding Aids

This collection consists of twenty-six glass plates slides used to teach Astronomy at Georgia Southern Teachers College, probably in the 1930s. They were produced by the Eastern Science Supply Company of Boston.

Find this collection in the University Libraries' catalog.

Target Mass Effects In Parton Quasi-Distributions, A. V. Radyushkin

Physics Faculty Publications

We study the impact of non-zero (and apparently large) value of the nucleon mass M on the shape of parton quasi-distributions Q(y, p₃), in particular on its change with the change of the nucleon momentum p_3. We observe that the usual target-mass corrections induced by the M-dependence of the twist-2 operators are rather small. Moreover, we show that within the framework based on parametrizations by transverse momentum dependent distribution functions (TMDs) these corrections are canceled by higher-twist contributions. We identify a novel source of kinematic target-mass dependence of TMDs and build models corrected for …

Photon Beam Asymmetry Σ In The Reaction →Γ P → Pω For Eγ = 1.152 To 1.876 Gev, P. Collins, B. G. Ritchie, M. Dugger, F. J. Klein, A. V. Anisovich, E. Klempt, V. A. Nikonov, A. Sarantsev, K. P. Adhikari, S. Adhikari, D. Adikaram, G. Charles, M. Khachatryan, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao

Physics Faculty Publications

Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ → p → ω p are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson …

Possible Pair-Instability Supernovae At Solar Motallicity From Magnetic Stellar Progenitors, Cyril Georgy, Georges Meynet, Sylvia Ekström, Gregg A. Wade, Véronique Petit, Zsolt Keszthelyi, Raphael Hirschi

Aerospace, Physics, and Space Science Faculty Publications

Near-solar metallicity (and low-redshift) pair-instability supernova (PISN) candidates challenge stellar evolution models. Indeed, at such a metallicity, even an initially very massive star generally loses so much mass by stellar winds that it will avoid the electron-positron pair-creation instability. We use recent results showing that a magnetic field at the surface of a massive star can significantly reduce its effective mass-loss rate to compute magnetic models of very massive stars (VMSs) at solar metallicity and explore the possibility that such stars end as PISNe. We implement the quenching of the mass loss produced by a surface dipolar magnetic field into …

Studying The Photometric And Spectroscopic Variability Of The Magnetic Hot Supergiant Ζ Orionis Aa, Bram Buysschaert, Alexandre David-Uraz

Aerospace, Physics, and Space Science Faculty Publications

Massive stars play a significant role in the chemical and dynamical evolution of galaxies. However, much of their variability, particularly during their evolved supergiant stage, is poorly understood. To understand the variability of evolved massive stars in more detail, we present a study of the O9.2Ib supergiant ζ Ori Aa, the only currently confirmed supergiant to host a magnetic field. We have obtained two-color space-based BRIght Target Explorer photometry (BRITE) for ζ Ori Aa during two observing campaigns, as well as simultaneous ground-based, high-resolution optical CHIRON spectroscopy. We perform a detailed frequency analysis to detect and characterize the star's periodic …

The Puzzling Case Of The Radio-Loud Qso 3c 186: A Gravitational Wave Recoiling Black Hole In A Young Radio Source?, Marco Chiaberge, Eric S. Perlman

Aerospace, Physics, and Space Science Faculty Publications

Context. Radio-loud active galactic nuclei with powerful relativistic jets are thought to be associated with rapidly spinning black holes (BHs). BH spin-up may result from a number of processes, including accretion of matter onto the BH itself, and catastrophic events such as BH-BH mergers. Aims. We study the intriguing properties of the powerful (Lbol ∼ 1047 erg s-1) radio-loud quasar 3C 186. This object shows peculiar features both in the images and in the spectra. Methods. We utilize near-IR Hubble Space Telescope (HST) images to study the properties of the host galaxy, and HST UV and Sloan Digital Sky Survey …

Characterizing The Source Properties Of Terrestrial Gamma Ray Flashes, Joseph R. Dwyer, Ningyu Liu, J. Eric Grove, Hamid K. Rassoul, David M. Smith

Aerospace, Physics, and Space Science Faculty Publications

Monte Carlo simulations are used to determine source properties of terrestrial gamma ray flashes (TGFs) as a function of atmospheric column depth and beaming geometry. The total mass per unit area traversed by all the runaway electrons (i.e., the total grammage) during a TGF, Ξ, is introduced, defined to be the total distance traveled by all the runaway electrons along the electric field lines multiplied by the local air mass density along their paths. It is shown that key properties of TGFs may be directly calculated from Ξ and its time derivative, including the gamma ray emission rate, the current …

A Test Of The Interstellar Boundary Explorer Ribbon Formation In The Outer Heliosheath, Konstantin V. Gamayunov, Jacob Heerikhuisen, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

NASA's Interstellar Boundary EXplorer (IBEX) mission is imaging energetic neutral atoms (ENAs) propagating to Earth from the outer heliosphere and local interstellar medium (LISM). A dominant feature in all ENA maps is a ribbon of enhanced fluxes that was not predicted before IBEX. While more than a dozen models of the ribbon formation have been proposed, consensus has gathered around the so-called secondary ENA model. Two classes of secondary ENA models have been proposed; the first class assumes weak scattering of the energetic pickup protons in the LISM, and the second class assumes strong but spatially localized scattering. Here we …

2d Full-Wave Simulation Of Waves In Space And Tokamak Plasmas, Jay R. Johnson, Eun-Hwa Kim, Nicola Bertelli, Ernest Valeo, Joel Hosea

Faculty Publications

Simulation results using a 2D full-wave code (FW2D) for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry) and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC) waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result …