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Articles 181 - 210 of 461

Full-Text Articles in Other Astrophysics and Astronomy

A Detailed X-Ray Analysis Of The Cold Front In Relics Cluster A2163, Anne Poy Jan 2021

A Detailed X-Ray Analysis Of The Cold Front In Relics Cluster A2163, Anne Poy

CMC Senior Theses

Galaxy clusters are the largest gravitationally bound objects in the Universe. Studying them can teach us about how they merge and grow, which in turn provides unparalleled information about the history of the evolution of the Universe. X-ray observations of galaxy clusters have uncovered substructure in the hot, X-ray emitting gas known as the intracluster mediums (ICM). Substructure indicates that the ICM has been churned up, possibly by a significant off-axis merger event. This substructure includes cold fronts, sloshing spirals, and shocks. We present deep Chandra observations of the merging cluster Abell 2163. We investigate the global spectrum and find …


Identification And Classification Of Radio Pulsar Signals Using Machine Learning, Di Pang Jan 2021

Identification And Classification Of Radio Pulsar Signals Using Machine Learning, Di Pang

Graduate Theses, Dissertations, and Problem Reports (ETD)

Automated single-pulse search approaches are necessary as ever-increasing amount of observed data makes the manual inspection impractical. Detecting radio pulsars using single-pulse searches, however, is a challenging problem for machine learning because pul- sar signals often vary significantly in brightness, width, and shape and are only detected in a small fraction of observed data.

The research work presented in this dissertation is focused on development of ma- chine learning algorithms and approaches for single-pulse searches in the time domain. Specifically, (1) We developed a two-stage single-pulse search approach, named Single- Pulse Event Group IDentification (SPEGID), which automatically identifies and clas- …


Investigation On The Use Of Small Aperture Telescopes For Leo Satellite Orbit Determination, Luis R. Curiel Iii Dec 2020

Investigation On The Use Of Small Aperture Telescopes For Leo Satellite Orbit Determination, Luis R. Curiel Iii

Master's Theses

The following thesis regards the use of small aperture telescopes for space domain awareness efforts. The rapidly populating space domain was motivation for the development of a new operation scheme to conduct space domain awareness feasibility studies using small telescopes. Two 14-inch Schmidt-Cassegrain Telescopes at the California Polytechnic State University and the Air Force Research Lab in Kirtland AFB, NM, in conjunction with a dedicated CCD camera and a commercial DSLR camera, were utilized to conduct optical observations on satellites in Earth orbit.

Satellites were imaged during August 2019, and from January 2020 to March 2020, resulting in the collection …


High Level Ab Initio Study Of The Energetic And Spectroscopic Properties Of [Al,S,O]X (X=0,+1) And Its Potential For Detection In Space, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco Nov 2020

High Level Ab Initio Study Of The Energetic And Spectroscopic Properties Of [Al,S,O]X (X=0,+1) And Its Potential For Detection In Space, Vincent J. Esposito, Tarek Trabelsi, Joseph S. Francisco

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Highly reliable molecular properties have been computed for the [Al, S, O]x (x = 0, +1) molecular system. Spectroscopic parameters are predicted from analysis of each isomer’s 3D potential energy surface calculated using the explicitly correlated multireference configuration interaction method, including the Davidson correction (MRCI-F12+Q). These parameters provide an accurate prediction of spectroscopic data that can be used in laboratory and observational studies of these molecules. Linear-SAlO is expected to have a large permanent dipole moment suitable for detection in the circumstellar envelopes of large, evolved, oxygen-rich stars such as VY Canis Majoris, IK Tauri, and R Doradus. …


Telescope Parallel Actuator Mount: Control And Testing, Samuel S. Artho-Bentz Nov 2020

Telescope Parallel Actuator Mount: Control And Testing, Samuel S. Artho-Bentz

Master's Theses

This thesis approaches the task of designing a control system for the Parallel Actuator Mount developed by Dr. John Ridgely and Mr. Garrett Gudgel. It aims to create a base framework that directly controls the telescope and can be expanded to accept external command. It incorporates lower priced components and develops more easily approachable software with great functionality. An open-loop method for velocity control is established. Developing repeatable tests is a major focus. Testing finds the control methods developed result in velocity error of less than 5% and position error of less than 1.5% despite several mechanical issues and inaccuracies. …


Understanding Atmospheres Across The Stellar-Substellar Boundary, Eileen C. Gonzales Sep 2020

Understanding Atmospheres Across The Stellar-Substellar Boundary, Eileen C. Gonzales

Dissertations, Theses, and Capstone Projects

Complexities in the atmospheres of sources that straddle the boundary between low-mass stars and planets drive the spectral features we observe and the fundamental parameters that we derive. In an effort to understand the underlying cause of these spectral features, this work examines low-mass stars and brown dwarfs using two approaches: distance-calibrated spectral energy distributions (SEDs) and atmospheric retrievals. SEDs allow for the determination of semi-empirical fundamental parameters, while atmospheric retrievals allow us to derive the atmospheric structure and composition, as well as extrapolated fundamental parameters for a source. Low-metallicity and high surface gravity sources, known as subdwarfs, are the …


Binary Neutron Star Mergers: Testing Ejecta Models For High Mass-Ratios, Allen Murray Aug 2020

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 …


Relativity Lite: A Pictorial Translation Of Einstein’S Theories Of Motion And Gravity, Jack C. Straton Aug 2020

Relativity Lite: A Pictorial Translation Of Einstein’S Theories Of Motion And Gravity, Jack C. Straton

PDXOpen: Open Educational Resources

Relativity Lite is designed for the General Astronomy sequence (PH 361-2U, SCI 315-6U) whose primary book glosses over Special Relativity and General Relativity while trying to explain the Cosmology that is based on those subjects. Relativity Lite translates the mathematical equations conventional relativity texts rely upon into pictures that are readily understood and contain within them the mathematical essentials. This book provides the comprehensive coverage needed to understand, in sufficient depth, these three linked areas of our reality.

Readers seeking this knowledge on their own, and those in other courses for nonscientists, may also find it helpful.

Adopt/Adapt
If you …


Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight, Kristine Ferrone Aug 2020

Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight, Kristine Ferrone

Dissertations and Theses (Open Access)

Exploration of interplanetary space presents dramatic hazards to human survival.

Space radiation hazards outside the protection of the Earth’s magnetosphere can

produce both acute and chronic health risks and thus become limiting factors for

NASA’s planned mission to Mars by the 2030s. Radiation exposure on a Mars mission

is delivered primarily by high energy ions from galactic cosmic rays and moderate

energy protons from solar particle events. The chronic radiation dose due to galactic

cosmic rays on a typical Mars mission is on the order of 1 Sv, and additional acute

radiation dose from solar flares can reach over 4 …


Computational Astronomy: Classification Of Celestial Spectra Using Machine Learning Techniques, Gayatri Milind Hungund May 2020

Computational Astronomy: Classification Of Celestial Spectra Using Machine Learning Techniques, Gayatri Milind Hungund

Master's Projects

Lightyears beyond the Planet Earth there exist plenty of unknown and unexplored stars and Galaxies that need to be studied in order to support the Big Bang Theory and also make important astronomical discoveries in quest of knowing the unknown. Sophisticated devices and high-power computational resources are now deployed to make a positive effort towards data gathering and analysis. These devices produce massive amount of data from the astronomical surveys and the data is usually in terabytes or petabytes. It is exhaustive to process this data and determine the findings in short period of time. Many details can be missed …


Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener May 2020

Probing The Magnetic Fields In Cosmic Web Filaments, Andrew L. Mizener

Macalester Journal of Physics and Astronomy

We present a project to constrain the properties of magnetic fields in Cosmic Web filaments. We first perform rotation measure (RM) synthesis on 24 S-band Karl G Jansky Very Large Array (VLA) observations of moderate-redshift active galactic nuclei (AGN). These observations are combined with an existing catalog of Cosmic Web filaments in order to determine the number of filaments a given sight-line passes near or through. By tracking how observables such as rotation measure and polarization fraction change as a function of the number of intervening cosmic web filaments, we take the first steps towards providing observational constraints on the …


Mineral-Surface Chemistry Of Hydroxyapatite And Urea-Rich Solutions, Estefania Garcia May 2020

Mineral-Surface Chemistry Of Hydroxyapatite And Urea-Rich Solutions, Estefania Garcia

Master of Science in Chemical Sciences Theses

On this planet the development of life requires six essential elements: C, H, O, N, P, and S. These elements are present in gaseous form, with the exception of phosphorus, which is primarily found in solid mineral sources. Phosphorus in biological systems is significant through its involvement in metabolic functions (e.g., Coenzyme A), cell structure (i.e., phospholipid membranes), and genetic storage/transfer (i.e., phosphodiester bonds in DNA and RNA). However, an ambiguity remains with the assimilation of phosphorus in biological systems, caused by its habitual presence in insoluble phosphate mineral sources. Recent research has found that insoluble phosphate …


Towards Gross-Pitaevskiian Description Of Solar System & Galaxies, Florentin Smarandache, Victor Christianto, Yunita Umniyati May 2020

Towards Gross-Pitaevskiian Description Of Solar System & Galaxies, Florentin Smarandache, Victor Christianto, Yunita Umniyati

Branch Mathematics and Statistics Faculty and Staff Publications

In this paper, we argue that Gross-Pitaevskii model can be a more complete description of both solar system and spiral galaxies, especially taking into account the nature of chirality and vortices in galaxies. We also hope to bring out some correspondence among existing models, e.g., the topological vortex approach, Burgers equation in the light of KAM theory, and the Cantorian Navier-Stokes approach. We hope further investigation can be done around this line of approach.


Automated Spectroscopic Detection And Mapping Using Alma And Machine Learningtechniques, Steven Cocke, Andrew Wilkins, Josephine Mcdaniel, John Santerre, Conor Nixon Apr 2020

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 …


Perfect Circles: A Study Of The Scattering Regions Of Wolf Rayet Binary Stars, Stella Yoos, Jennifer Hoffman, Andrew Fullard Apr 2020

Perfect Circles: A Study Of The Scattering Regions Of Wolf Rayet Binary Stars, Stella Yoos, Jennifer Hoffman, Andrew Fullard

DU Undergraduate Research Journal Archive

Although we have been able to develop an understanding of many aspects of stellar evolution and formation, a few key gaps remain. One is the fate of massive binary star systems composed of Wolf-Rayet (WR) and O-type stars. In these WR + O binaries, the stellar winds surrounding these stars collide, creating a complex interaction region in which light from the stars scatters and becomes polarized. To study these scattering regions, I employ a technique that allows me to map the polarization of the light emitted from these stars and track its variation over the binary orbit. I found that …


Response To Pitkanen’S Solar System Model: Towards Gross-Pitaevskiian Description Of Solar System And Galaxies And More Evidence Of Chiral Superfluid Vortices, Victor Christianto, Florentin Smarandache, Yunita Umniyati Apr 2020

Response To Pitkanen’S Solar System Model: Towards Gross-Pitaevskiian Description Of Solar System And Galaxies And More Evidence Of Chiral Superfluid Vortices, Victor Christianto, Florentin Smarandache, Yunita Umniyati

Branch Mathematics and Statistics Faculty and Staff Publications

In a new paper in recent issue of this journal (PSTJ), Prof. M. Pitkanen describes a solar system model inspired by spiral galaxies. While we appreciate his new approach, we find it lacks substantial discussion on the nature of vortices and chirality in galaxy. Therefore we submit a viewpoint that Gross-Pitaevskii model can be a more complete description of both solar system and also spiral galaxies, especially taking into account the nature of chirality and vortices in galaxies. In this article, we also hope to bring out some correspondence among existing models, so we discuss shortly: the topological vortice approach, …


Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv Mar 2020

Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv

Theses and Dissertations

In the future, a hazardous asteroid will find itself on a collision course with Earth. It is an inevitability; the question is not if, but when. For asteroids of moderate size or larger, a nuclear device is one of humanity's only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how changing the output neutron energy from a nuclear device detonation affects asteroid deflection. The notional asteroid target was 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. To calculate the …


A 3-Year Sample Of Almost 1,600 Elves Recorded Above South America By The Pierre Auger Cosmic-Ray Observatory, A. Aab, R. Engel, Gregory Snow, Pierre Auger Cosmic-Ray Observatory, 390 Co-Authors Jan 2020

A 3-Year Sample Of Almost 1,600 Elves Recorded Above South America By The Pierre Auger Cosmic-Ray Observatory, A. Aab, R. Engel, Gregory Snow, Pierre Auger Cosmic-Ray Observatory, 390 Co-Authors

Gregory Snow Publications

Elves are a class of transient luminous events, with a radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms.We report the observation of 1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located in the Mendoza province of Argentina with a viewing footprint for elve observations of 3 · 106 km2, reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for severe convective thunderstorms. Primarily …


A Numerical Approach To Modeling Submoons And Investigating Stability Regions, Josephine Spiegelberg Jan 2020

A Numerical Approach To Modeling Submoons And Investigating Stability Regions, Josephine Spiegelberg

Honors Program Theses

The recent discovery of the Neptune-sized exomoon candidate Kepler-1625bi (Teachey et al. 2018) has prompted a wave of research into the possibility of such a large satellite hosting its own moons, or submoons. These submoons have a lot in common with moons, and lessons from moon stability calculations can help to understand submoon behavior and stability. Past submoon research has focused on determining stability regions for these submoons using simplified models of the body’s tidal evolution (Reid 1973, Conrad 1985, Kollmeier and Raymond 2019). In order to provide a more detailed understanding of submoon behavior, a Fortran N-Body code was …


Creating A Sample Of Off-Color Galaxies Using Big Data Tools, Christopher Becker Jan 2020

Creating A Sample Of Off-Color Galaxies Using Big Data Tools, Christopher Becker

Honors Program Theses

This thesis begins an investigation into the presence of off-colored galaxies in the Sloan Digital Sky Survey. Through establishing the emergence and history of Astroinformatics, the thesis introduces the concepts surrounding both off-color galaxies and the Big Data tools helpful in analyzing the data to find them. A discussion of initial implementation methods and revised implementation due to difficulties with previous plans follows. Results are presented, with well in excess of 500,000 candidates for off-color galaxies present in the sample. Conclusions are then drawn regarding such a large sample and the implications this may have on the conventional understanding of …


There Is No Constant In Physics: A Neutrosophic Explanation, Victor Christianto, Robert Neil Boyd, Florentin Smarandache Jan 2020

There Is No Constant In Physics: A Neutrosophic Explanation, Victor Christianto, Robert Neil Boyd, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In Neutrosophic Logic, a basic assertion is that there are variations of about everything that we can measure; the variations surround three parameters called T,I,F (truth, indeterminacy, falsehood) which can take a range of values. Similarly, in this paper we consider NL applications in physics constants. Those constants actually all have a window of plus and minus values, relative to the average value of the constant. For example, speed of light, c, can vary in a window up to +/- 3000 m/s. Therefore it should be written: 300000 km/s +/- 3 km/s. We also discuss some implications of this new …


A Review On Superluminal Physics And Superluminal Communication In Light Of The Neutrosophic Logic Perspective, Victor Christianto, Florentin Smarandache Jan 2020

A Review On Superluminal Physics And Superluminal Communication In Light Of The Neutrosophic Logic Perspective, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In a recent paper, we describe a model of quantum communication based on combining consciousness experiment and entanglement, which can serve as impetus to stop 5G-network-caused diseases. Therefore, in this paper we consider superluminal physics and superluminal communication as a bridge or intermediate way between subluminal physics and action-at-a-distance (AAAD) physics, especially from neutrosophic logic perspective. Although several ways have been proposed to bring such a superluminal communication into reality, such as Telluric wave or Telepathy analog of Horejev and Baburin, here we also review two possibilities: quaternion communication and also quantum communication based on quantum noise. Further research is …


On The Detection Of Gw190814, Matthew E. Gill Jan 2020

On The Detection Of Gw190814, Matthew E. Gill

Theses and Dissertations

The eld of gravitational wave astronomy is currently at an all time high. The

rst half of the most recent observing run (April 1, 2019 - September 30, 2019) yielded

a total of 39 gravitational wave detections, including 13 from sources which had not

been identied by other astronomical observation methods before. This is three times

as many detections than were measured in the rst two observing runs combined.

In this paper, the design sensitivity decisions leading to this unprecedented rate of

detection are explored. In particular, we detail the nature of the LIGO and VIRGO

gravitational wave interferometers. One …


Cosmic-Ray Acceleration In The Cygnus Ob2 Stellar Association, Binita Hona Jan 2020

Cosmic-Ray Acceleration In The Cygnus Ob2 Stellar Association, Binita Hona

Dissertations, Master's Theses and Master's Reports

The Cygnus region of our Galaxy consists of an active star forming region and a wealth of various astrophysical sources such as pulsar wind nebulae (PWN), supernova remnants (SNRs), and massive star clusters. Massive stellar clusters and associations have been postulated as possible sources of cosmic rays (CRs) in our Galaxy. One example of a gamma-ray source associated with a stellar association lies in the Cygnus region known as the "Cygnus Cocoon". It is an extended region of gamma-ray emission in the Cygnus X region and attributed to a possible superbubble with freshly accelerated CRs which are hypothesized to produce …


The Future Of Space Governance, Melissa J. Durkee Jan 2020

The Future Of Space Governance, Melissa J. Durkee

Scholarly Works

Fifty years after the first moonwalk, the prospect for a new set of multilateral agreements governing outer space is remote, yet the legal questions raised by activity in space are mounting. With little prospect of new treaties, nations will need to make do with existing treaty law, generate customary rules to govern new applications, or develop forms of sub-legal understanding and cooperation. This special conference issue of the Georgia Journal of International and Comparative Law addresses these questions.


Modeling The Galactic Compact Binary Neutron Star Population And Studying The Double Pulsar System, Nihan Pol Jan 2020

Modeling The Galactic Compact Binary Neutron Star Population And Studying The Double Pulsar System, Nihan Pol

Graduate Theses, Dissertations, and Problem Reports (ETD)

Binary neutron star (BNS) systems consisting of at least one neutron star provide an avenue for testing a broad range of physical phenomena ranging from tests of General Relativity to probing magnetospheric physics to understanding the behavior of matter in the densest environments in the Universe. Ultra-compact BNS systems with orbital periods less than few tens of minutes emit gravitational waves with frequencies ~mHz and are detectable by the planned space-based Laser Interferometer Space Antenna (LISA), while merging BNS systems produce a chirping gravitational wave signal that can be detected by the ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO). Thus, BNS …


Searching For Needles In The Cosmic Haystack, Thomas Ryan Devine Jan 2020

Searching For Needles In The Cosmic Haystack, Thomas Ryan Devine

Graduate Theses, Dissertations, and Problem Reports (ETD)

Searching for pulsar signals in radio astronomy data sets is a difficult task. The data sets are extremely large, approaching the petabyte scale, and are growing larger as instruments become more advanced. Big Data brings with it big challenges. Processing the data to identify candidate pulsar signals is computationally expensive and must utilize parallelism to be scalable. Labeling benchmarks for supervised classification is costly. To compound the problem, pulsar signals are very rare, e.g., only 0.05% of the instances in one data set represent pulsars. Furthermore, there are many different approaches to candidate classification with no consensus on a best …


Searches For Fast Radio Bursts Using Machine Learning, Devansh Agarwal Jan 2020

Searches For Fast Radio Bursts Using Machine Learning, Devansh Agarwal

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fast Radio bursts (FRBs) are enigmatic astrophysical events with millisecond durations and flux densities in the range 0.1-100 Jy, with the prototype source discovered by Lorimer et al. (2007). Like pulsars, FRBs show the characteristic inverse square sweep in observing frequency due to propagation through an ionized medium. This effect is quantified by the dispersion measure (DM). Unlike pulsars, FRBs have anomalously high DMs, which are consistent with an extragalactic origin. Over 100 FRBs have been published at the time of writing, and 13 have been conclusively identified with host galaxies with spectroscopically determined redshifts in the range 0.003 ≤ …


New Foundation In The Sciences: Physics Without Sweeping Infinities Under The Rug, Florentin Smarandache, Victor Christianto, Robert Neil Boyd Dec 2019

New Foundation In The Sciences: Physics Without Sweeping Infinities Under The Rug, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

It is widely known among the Frontiers of physics, that “sweeping under the rug” practice has been quite the norm rather than exception. In other words, the leading paradigms have strong tendency to be hailed as the only game in town. For example, renormalization group theory was hailed as cure in order to solve infinity problem in QED theory. For instance, a quote from Richard Feynman goes as follows: “What the three Nobel Prize winners did, in the words of Feynman, was "to get rid of the infinities in the calculations. The infinities are still there, but now they can …


Measurements Of The 16c + 12c And 16c + 13c Fusion Cross Sections With Implications For Astrophysics, Ashley Ann Hood Nov 2019

Measurements Of The 16c + 12c And 16c + 13c Fusion Cross Sections With Implications For Astrophysics, Ashley Ann Hood

LSU Doctoral Dissertations

The fusion of neutron-rich nuclei is of interest to nuclear astrophysics and nuclear structure. X-ray superbursts are powered by runaway thermonuclear burning deep inside of a neutron star, where heating from the pycnonuclear fusion of neutron-rich isotopes is an important heat source. Experimental measurements of fusion cross sections of neutron-rich isotopes have provided insights regarding nucleon transfer and nuclear structure properties affecting fusion. Recently, the 15C + 12C total fusion cross section was measured using a 15C beam produced by the in-flight beam production facility, which is part of the Argonne Tandem LINAC Accelerator System (ATLAS) at …