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Median Energy Imaging Of Supernova Remnants With Chandra X-Ray Observatory, Anne Blackwell 2019 William & Mary

Median Energy Imaging Of Supernova Remnants With Chandra X-Ray Observatory, Anne Blackwell

Undergraduate Honors Theses

Supernova remnants (SNRs) play an important role in shaping the energy density, chemical enrichment, and interstellar medium (ISM) of galaxies, and in our understanding of stellar evolution. Due to the high plasma temperatures of SNRs, they primarily emit X-rays. Using data collected with the Chandra observatory, we study a novel statistical imaging analysis technique to probe the underlying structure and physical properties of DEM L71, a SNR in the Large Magellanic Cloud. We used the statistical properties of the photons within an image pixel, such as the median energy, to make images of the energetics across the SNR. We have ...


Induced Magnetic Dipole On Jupiter’S Moon Europa, Luke Francis, Michele Zanolin 2019 Embry-Riddle Aeronautical University

Induced Magnetic Dipole On Jupiter’S Moon Europa, Luke Francis, Michele Zanolin

Student Works

Physics can have some of the most unique and extraordinary applications of basic principles applied on a larger scale. This paper will explore the properties of induced magnetic dipoles and will examine this phenomenon directly from Jupiter's moon, Europa. These properties will be used to determine if there is liquid water beneath its icy surface and how this conclusion was verified. This will be accomplished using the concepts of magnetic dipoles and induced currents. Recent missions have also revealed estimates of the depth of Europa's subsurface ocean. There have been many measurements taken of Europa's magnetic field ...


The Relationship Between Radial Gas Pressure Gradient And The Planetesimal Mass Distribution Of A Protoplanetary Disk, Charles Abod 2019 University of Colorado, Boulder

The Relationship Between Radial Gas Pressure Gradient And The Planetesimal Mass Distribution Of A Protoplanetary Disk, Charles Abod

Undergraduate Honors Theses

The streaming instability is a mechanism that produces regions of particle overdensity in protoplanetary disks. These over-densities gravitationally collapse to form planetesimals. Although it is well known that the extent of particle clumping is dependent on the radial gas pressure gradient, the relationship between pressure gradient and planetesimal properties is not known. We carry out very high resolution local, shearing box simulations (i.e., a small co-rotating patch) of a protoplanetary disk to study the effect of the radial pressure gradient on the streaming instability and resulting planetesimal properties. We find that the pre-collapse structure of particles grows increasingly axisymmetric ...


Multi-Diffusion Domain Modeling Of Meteorite 40ar/39ar Data, Evan Tucker 2019 University of Colorado, Boulder

Multi-Diffusion Domain Modeling Of Meteorite 40ar/39ar Data, Evan Tucker

Undergraduate Honors Theses

The majority of 40Ar/39Ar analyses involving extraterrestrial samples were collected from bulk rock samples due to fine grain sizes. This present challenges in modeling the diffusion kinetics and thermal histories of these samples because of the presence of multiple-diffusion domains. Since Lovera et al. (1989) developed the multi-diffusion domain (MDD) method of modeling, many attempts have been made to automate the modeling process. However, existing software to model diffusion parameters and thermal histories falls short in that it is either restricted in availability, restricted in flexibility, or is cumbersome to use. I have created a new program ...


The Non-Linear Dynamics Of Barred Galaxy Evolution In Lcdm, Michael Petersen 2019 University of Massachusetts Amherst

The Non-Linear Dynamics Of Barred Galaxy Evolution In Lcdm, Michael Petersen

Doctoral Dissertations

The study of barred galaxy dynamics has had many successes explaining observed phenomena in barred galaxies both locally and distant, including our own Milky Way, a barred galaxy. However, the majority of this knowledge arises from either (a) analytic linear theory, which by definition cannot inform nonlinear processes, or (b) simulations which are subject to an unconstrained host of evolutionary mechanisms, including `real' dynamical processes and `artificial' numerical processes, and are thus difficult to interpret. This work chooses a path which attempts to take the best of both techniques, employing n-body simulations in the Lambda cold dark matter paradigm designed ...


The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat 2018 University of Kentucky

The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat

Posters-at-the-Capitol

Lunar swirls are complex patterns on the Moon with distinct brightness signatures and magnetic characteristics. Current research has suggested that the formation of lunar swirls relies on local magnetic fields to shield impinging solar wind, based on a shift in electromagnetic wavelength peaks related to solar radiation and space weathering. Our research combined recent models and methods to characterize these anomalies at the surface of the Moon, exploring the effects of field strength and position. We have produced a high resolution map of a famous swirl named Reiner Gamma using magnetic dipole modeling. These maps and models are considered when ...


4 - A Flexible Model For Investigating The Properties Of Starspots: Comparison Of Model Predictions To Observed Data, Amanda Ash 2018 University of North Georgia

4 - A Flexible Model For Investigating The Properties Of Starspots: Comparison Of Model Predictions To Observed Data, Amanda Ash

Georgia Undergraduate Research Conference (GURC)

Accurate age estimates provide a wealth of information about the mechanisms of different astrophysical phenomenon. However, current methods of applying stellar evolution models to obtain these estimates has proven to be flawed, with models having little consistency. It has been speculated the source of this inconsistency may arise from deviations in stellar properties due to the presence of dark blemishes, starspots, present on young cool stars (Feiden, 2016). Using predictions of expected properties from the flexible starspot model to observed properties of various open clusters, we aim to define what starspot properties bring model predictions into agreement with observed data ...


5 - Irregularities In Young Stellar Models: Are Starspots To Blame?, Jessica Hamilton 2018 University of North Georgia

5 - Irregularities In Young Stellar Models: Are Starspots To Blame?, Jessica Hamilton

Georgia Undergraduate Research Conference (GURC)

Starspots are dark areas on a star’s surface formed by intense magnetic fields that actively suppress the flow of energy, causing the area to become cooler and darker than its surroundings. Starspots threaten a star’s equilibrium because they prevent energy from leaving the star, causing a buildup of pressure. The prevailing assumption is that increased pressure will cause the star to inflate, producing a cooler and larger star. For this reason, starspots have been proposed to explain why some stars appear cooler and larger than we expect. This requires energy blocked by a spot to be trapped deep ...


The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina 2018 The University of Western Ontario

The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina

Electronic Thesis and Dissertation Repository

Currently, Mars appears to be in a ‘frozen’ and ‘dry’ state, with the clear majority of the planet’s surface maintaining year-round sub-zero temperatures. However, the discovery of features consistent with landforms found in periglacial environments on Earth, suggests a climate history for Mars that may have involved freeze and thaw cycles. Such landforms include hummocky, polygonised, scalloped, and pitted terrains, as well as ice-rich deposits and gullies, along the mid- to high-latitude bands, typically with no lower than 20o N/S. The detection of near-surface and surface ice via the Phoenix lander, excavation of ice via recent impact cratering ...


Astromimetics: The Dawn Of A New Era For (Bio)Materials Science?, Vuk Uskoković, Victoria M. Wu 2018 Chapman University

Astromimetics: The Dawn Of A New Era For (Bio)Materials Science?, Vuk Uskoković, Victoria M. Wu

Pharmacy Faculty Articles and Research

Composite, multifunctional fine particles are likely to be at the frontier of materials science in the foreseeable future. Here we present a submicron composite particle that mimics the stratified structure of the Earth by having a zero-valent iron core, a silicate/silicide mantle, and a thin carbonaceous crust resembling the biosphere and its biotic deposits. Particles were formulated in a stable colloidal form and made to interact with various types of healthy and cancer cells in vitro. A selective anticancer activity was observed, promising from the point of view of the intended use of the particles for tumor targeting across ...


Strong Evidence For The Density-Wave Theory Of Spiral Structure From A Multi-Wavelength Study Of Disk Galaxies, Hamed Pour-Imani 2018 University of Arkansas, Fayetteville

Strong Evidence For The Density-Wave Theory Of Spiral Structure From A Multi-Wavelength Study Of Disk Galaxies, Hamed Pour-Imani

Theses and Dissertations

The density-wave theory of spiral structure, though first proposed as long ago as the mid-1960s by C.C. Lin and F. Shu (Lin & Shu, 1964; Bertin & Lin, 1996; Shu, 2016), continues to be challenged by rival theories, such as the manifold theory. One test of these theories which has been proposed is that the pitch angle of spiral arms for galaxies should vary with the wavelength of the image in the density-wave theory, but not in the manifold theory. The reason is that stars are born in the density wave but move out of it as they age. In this dissertation, I combined large ...


Impact Melt Emplacement On Mercury, Jeffrey Daniels 2018 The University of Western Ontario

Impact Melt Emplacement On Mercury, Jeffrey Daniels

Electronic Thesis and Dissertation Repository

Impact cratering is an abrupt, spectacular process that occurs on any world with a solid surface. On Earth, these craters are easily eroded or destroyed through endogenic processes. The Moon and Mercury, however, lack a significant atmosphere, meaning craters on these worlds remain intact longer, geologically. In this thesis, remote-sensing techniques were used to investigate impact melt emplacement about Mercury’s fresh, complex craters. For complex lunar craters, impact melt is preferentially ejected from the lowest rim elevation, implying topographic control. On Venus, impact melt is preferentially ejected downrange from the impact site, implying impactor-direction control. Mercury, despite its heavily-cratered ...


Education, Support, And Results For Wyoming Participants In The Citizen Cate (Continental-America Telescopic Eclipse) Experiment, Gabriel Miller 2018 University of Wyoming

Education, Support, And Results For Wyoming Participants In The Citizen Cate (Continental-America Telescopic Eclipse) Experiment, Gabriel Miller

Honors Theses AY 17/18

Throughout the spring and summer of 2017, the Citizen CATE (Continental- America Telescopic Eclipse) Experiment was active in Wyoming and across the contiguous United States, with the goal of achieving an unbroken line of citizen- operated telescopes and cameras along the path of totality for the August eclipse. Eleven sites were active in Wyoming, composed of teachers, students, amateur and professional astronomers, and interested members of the community. In two large educational sessions, as well as several localized practice events, these groups were trained to use the telescopes and cameras provided for them. Working closely with the National Solar Observatory ...


An Investigation Into The Suitability Of Sulfate-Reducing Bacteria As Models For Martian Forward Contamination, Maxwell M. W. Silver 2018 University of Arkansas, Fayetteville

An Investigation Into The Suitability Of Sulfate-Reducing Bacteria As Models For Martian Forward Contamination, Maxwell M. W. Silver

Theses and Dissertations

The NASA Planetary Protection policy requires interplanetary space missions do not compromise the target body for a current or future scientific investigation and do not pose an unacceptable risk to Earth, including biologic materials. Robotic missions to Mars pose a risk to planetary protection in the forms of forward and reverse contamination. To reduce these risks, a firm understanding of microbial response to Mars conditions is required. Sulfate-reducing bacteria are prime candidates for potential forward contamination on Mars. Understanding the potential for forward-contamination of sulfate-reducers on Mars calls for the characterization of sulfate-reducers under Mars atmosphere, temperature, and sulfate-brines. This ...


Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms, A. P. Dimmock, A. Osmane, T. I. Pulkkinen, K. Nykyri, E. Kilpua 2018 Aalto University

Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms, A. P. Dimmock, A. Osmane, T. I. Pulkkinen, K. Nykyri, E. Kilpua

Katariina Nykyri

The magnetosheath contains an array of waves, instabilities, and nonlinear magnetic structures which modify global plasma properties by means of various wave-particle interactions. The present work demonstrates that ion-scale magnetic field structures (∼0.2–0.5 Hz) observed in the dayside magnetosheath are statistically correlated to ion temperature changes on orders 10–20% of the background value. In addition, our statistical analysis implies that larger temperature changes are in equipartition to larger amplitude magnetic structures. This effect was more pronounced behind the quasi-parallel bow shock and during faster solar wind speeds. The study of two separate intervals suggests that this ...


The Dawn–Dusk Asymmetry Of Ion Density In The Dayside Magnetosheath And Its Annual Variability Measured By Themis, Andrew P. Dimmock, Tuija I. Pulkkinen, Adnane Osmane, Katariina Nykyri 2018 Aalto University

The Dawn–Dusk Asymmetry Of Ion Density In The Dayside Magnetosheath And Its Annual Variability Measured By Themis, Andrew P. Dimmock, Tuija I. Pulkkinen, Adnane Osmane, Katariina Nykyri

Katariina Nykyri

The local and global plasma properties in the magnetosheath play a fundamental role in regulating solar wind–magnetosphere coupling processes. However, the magnetosheath is a complex region to characterise as it has been shown theoretically, observationally and through simulations that plasma properties are inhomogeneous, non-isotropic and asymmetric about the Sun-Earth line. To complicate matters, dawn–dusk asymmetries are sensitive to various changes in the upstream conditions on an array of timescales. The present paper focuses exclusively on dawn–dusk asymmetries, in particularly that of ion density. We present a statistical study using THEMIS data of the dawn–dusk asymmetry of ...


Imf Dependence Of Energetic Oxygen And Hydrogen Ion Distributions In The Near-Earth Magnetosphere, H. Luo, E. A. Kronberg, K. Nykyri, K. J. Trattner, P. W. Daly, G. X. Chen, A. M. Du, Y. S. Ge 2018 Chinese Academy of Sciences

Imf Dependence Of Energetic Oxygen And Hydrogen Ion Distributions In The Near-Earth Magnetosphere, H. Luo, E. A. Kronberg, K. Nykyri, K. J. Trattner, P. W. Daly, G. X. Chen, A. M. Du, Y. S. Ge

Katariina Nykyri

Energetic ion distributions in the near-Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere and their transportation, acceleration, and losses in the near-Earth region. In this study, 11 years of energetic proton and oxygen observations (> ~274 keV) from Cluster/Research with Adaptive Particle Imaging Detectors were used to statistically study the energetic ion distributions in the near-Earth region. The dawn-dusk asymmetries of the distributions in three different regions (dayside magnetosphere, near-Earth nightside plasma sheet, and tail plasma sheet) are examined in Northern and Southern Hemispheres. The results show that the energetic ion distributions ...


Magnetic Field Design To Reduce Systematic Effects In Neutron Electric Dipole Moment Measurements, James Ryan Dadisman 2018 University of Kentucky

Magnetic Field Design To Reduce Systematic Effects In Neutron Electric Dipole Moment Measurements, James Ryan Dadisman

Theses and Dissertations--Physics and Astronomy

Charge-Conjugation (C) and Charge-Conjugation-Parity (CP) Violation is one of the three Sakharov conditions to explain via baryogenesis the observed baryon asymmetry of the universe (BAU). The Standard Model of particle physics (SM) contains sources of CP violation, but cannot explain the BAU. This motivates searches for new physics beyond the standard model (BSM) which address the Sakharov criteria, including high-precision searches for new sources of CPV in systems for which the SM contribution is small, but larger effects may be present in BSM theories. A promising example is the search for the electric dipole moment of the neutron (nEDM), which ...


Simulation Of Nonstationary Gaussian Process By Consecutive Conditioning, Kwan Ho Lee 2018 University of Colorado at Boulder

Simulation Of Nonstationary Gaussian Process By Consecutive Conditioning, Kwan Ho Lee

Applied Mathematics Graduate Theses & Dissertations

This thesis aims to develop the method of consecutive conditioning, which is used to directly simulate a stochastic process given an arbitrary covariance function. As a method for simulating stochastic processes, consecutive conditioning is useful in at least in three respects. While most methods require modeling of the covariance function prior to simulation, consecutive conditioning can be used with any arbitrary covariance function, thus introducing less error into the simulation than other methods. Second, consecutive conditioning allows us to perform very fast computations during simulation and can be used even by people who are not experts in modeling, unlike other ...


Correlation Between Emission Lines And Radio Luminosities Of Active Galactic Nuclei, Jessica Short-Long 2018 University of Kentucky

Correlation Between Emission Lines And Radio Luminosities Of Active Galactic Nuclei, Jessica Short-Long

Theses and Dissertations--Physics and Astronomy

Radio-loud active galactic nuclei (AGN) are one class of objects associated with accretion activity onto supermassive black holes in centers of massive galaxies. They are believed to be in a radiatively-inefficient accretion mode with low accretion rate. To understand this accretion mode, it is important to measure its radiative output at high energies (> 13.6eV), which can be traced through optical emission lines. However, little is known about their true radiative output. This is because no correlation between optical emission-line and radio luminosity has been found for the majority of low-luminosity radio AGN, which are often classified as low-excitation radio ...


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