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Full-Text Articles in Physical Sciences and Mathematics

Flare Emission Observed In High Resolution And Comparison With Numerical Modeling, Nengyi Huang Aug 2020

Flare Emission Observed In High Resolution And Comparison With Numerical Modeling, Nengyi Huang

Dissertations

As one of the most intense activities on the solar surface, flares have been extensively observed and studied ever since the first report. The standard model of solar flares has been established and commonly accepted. However, many limitations from the researching tools have left some of the problems unsolved or controversial. For example, the density of electrons in the corona is lower than it is required to activate the observed emission in HXR, and the mechanism that these electron beams can penetrate down to lower chromosphere is unclear. Many theoretical scenarios were suggested, and more observations had been in need. …


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 …


Astroalign: A Python Module For Astronomical Image Registration, Martin Beroiz, Juan B. Cabral, Bruno Sanchez Jul 2020

Astroalign: A Python Module For Astronomical Image Registration, Martin Beroiz, Juan B. Cabral, Bruno Sanchez

Physics and Astronomy Faculty Publications and Presentations

We present an algorithm implemented in the Astroalign Python module for image registration in astronomy. Our module does not rely on WCS information and instead matches three-point asterisms (triangles) on the images to find the most accurate linear transformation between them. It is especially useful in the context of aligning images prior to stacking or performing difference image analysis. Astroalign can match images of different point-spread functions, seeing, and atmospheric conditions.


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 …


Design And Modal Analysis Of An Ultra-Wideband Receiver For Green Bank Observatory, Alyssa Bulatek May 2020

Design And Modal Analysis Of An Ultra-Wideband Receiver For Green Bank Observatory, Alyssa Bulatek

Macalester Journal of Physics and Astronomy

The next generation of radio receivers for astronomy will be marked by tenfold improvements in sensitivity. These sensitive receivers will be useful for the detection of broadband fast radio bursts and other transients as well as the efficient discovery of radio recombination lines among many other scientific pursuits. One contribution to these improvements is an increase to decade receiver bandwidths. The Green Bank Observatory (GBO) is currently in the process of fabricating a new ultra-wideband (UWB; 0.7 to 4.2 GHz) receiver for the Green Bank Telescope (GBT). The UWB receiver will be used by the North American Nanohertz Observatory for …


Investigating The Stability Of Observed Low Semi-Major Axis Exoplanetary Systems With Hypothetical Outer Planets Using The Program Mercury6, Kendall Butler May 2020

Investigating The Stability Of Observed Low Semi-Major Axis Exoplanetary Systems With Hypothetical Outer Planets Using The Program Mercury6, Kendall Butler

Honors College

This project investigates the stability of observed planetary systems, and whether this stability remains in the presence of additional outer planets. This made use of the program Mercury6, an n-body integrator that computes the changes in planetary orbits over time. The Systems HD 136352, GJ 9827, and HD 7924 were studied with initial conditions taken from the available observational data. This information was curated using the online NASA Exoplanet archive of confirmed exoplanets. With these initial conditions, Mercury6 computed the changing planetary orbits of each system for 5 million years. For each of these systems, a single outer planet, which …


Determining The Rotational And Orbital Velocities Of Objects In The Solar System, Mark Jones May 2020

Determining The Rotational And Orbital Velocities Of Objects In The Solar System, Mark Jones

Undergraduate Honors Theses

Astronomers have been observing the night sky for many centuries to establish a better understanding for our universe and solar system. As part of their observations, astronomers characterize celestial bodies by fundamental properties such as mass, motion, and composition in order to provide further insight about the objects in question. As technology and science have evolved, the methods for measuring these properties have become more precise and accurate. One such methodology is known as spectroscopy, and it is a significant tool for observational astronomy. In this paper, we shall describe how we used astronomical spectroscopy to determine orbital and rotational …


Design And Construction Of A Computer Controlled Astronomical Spectropolarimeter, Jacob Marchio May 2020

Design And Construction Of A Computer Controlled Astronomical Spectropolarimeter, Jacob Marchio

Honors College

A theoretical description of a simple optical train, modulated signal based spectropolarimeter is discussed. The design includes, after the telescope optical tube (in this case, a 9.25” Schmidt Cassegrain), a rotating quarter waveplate (compensator), a fixed linear polarizer (analyzer), and transmission grating of 100l/mm, with a ZWO ASI290mm astronomical camera. The practical constraints on implementing such an instrument are discussed, and the construction of the spectropolarimeter is detailed, including the necessary optics, optomechanics, and electromechanics. The rotation and recording of the rotating compensator is facilitated by a motorized connection with proportional feedback control, and the uncertainty in measuring the angle …


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 …


Covid-19_Umaine News_Emera Astronomy Center Supports Covid-19 Research Efforts, University Of Maine Division Of Marketing And Communications Apr 2020

Covid-19_Umaine News_Emera Astronomy Center Supports Covid-19 Research Efforts, University Of Maine Division Of Marketing And Communications

Division of Marketing & Communications

Screenshot of Maine News release regarding the Emera Astronomy Center at the University of Maine contributing to global scientific research efforts to fight COVID-19.


In-Class Activities For Openstax Astronomy, Rosa Williams, Kimberly Shaw Apr 2020

In-Class Activities For Openstax Astronomy, Rosa Williams, Kimberly Shaw

Physics and Astronomy Ancillary Materials

This set of in-class activities in Microsoft Word format are intended to supplement OpenStax Astronomy. Topics include:

  • Atmospheric Gas
  • Celestial Sphere
  • Dwarf Planets
  • Earth Size
  • Earth Impact
  • Greenhouse Gases and Climate Change
  • Jovian Planet
  • Jovian Moon and Ring
  • Mars Atmosphere and Climate
  • Solar System Formation and Scale
  • Sunspots
  • Terrestrial Planet and Lunar Features
  • Venus Atmosphere and Climate


Host-Galaxy Morphology Of 14 Local Active Galaxies As Imaged By The Hubble Space Telescope, Tomas Henry Snyder Mar 2020

Host-Galaxy Morphology Of 14 Local Active Galaxies As Imaged By The Hubble Space Telescope, Tomas Henry Snyder

Physics

Active galactic nuclei (AGNs) are galaxies with super-massive black holes, that are undergoing accretion, at their centers. The study of these objects provides us with a deeper understanding of how the black holes evolved along with their host galaxies since black hole mass is highly correlated with bulge mass. A sample of 66 AGNs were imaged using the Hubble Space Telescope (HST) and 14 of those are analyzed in this paper to determine their structure, bulge luminosity, and bulge type. The program GALFIT is implemented to determine these parameters, that will be used in further research in the future. These …


A Writing Intensive Upper Division Astrophysics/Planetary Science Course, Laura M. Woodney Feb 2020

A Writing Intensive Upper Division Astrophysics/Planetary Science Course, Laura M. Woodney

Q2S Enhancing Pedagogy

This poster describes the major writing components of an upper division Astronomy or Planetary Science course. These components are intended to be integrated throughout the semester along with the content of the course. The papers the instructor chooses for the scaffolded assignments should compliment/enhance the content the students are learning in the course. This project used the "Backwards Design" method from Bean (2011, citation in poster): where the instructor first identifies the final project, determines what challenges the students will encounter attempting to do that project, and then builds scaffolded assignments intended to address each of these challenges. This presentation …


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 …


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

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 …


Historical Milestones In Astronomy: As Shown Through The Byu Special Collections Archives, Dan Broadbent Jan 2020

Historical Milestones In Astronomy: As Shown Through The Byu Special Collections Archives, Dan Broadbent

Faculty Publications

Science Research: The “Long Conversation”

  • Ideas in science can take a long time to develop.
  • How do they develop?
  • These books document a part of a conversation that began 447 years ago and spanned a 153 year period… documenting:
  • how the overall nature of the universe was worked out,
  • the establishment of the scientific method, and the boundaries of religious authority,
  • and culminated in Isaac Newton’s book that presented his three laws of motion that allow us to explore the universe to this day.


Significance Of Gravitational Nonlinearities On The Dynamics Of Disk Galaxies, Alexandre Deur, Corey Sargent, Balša Terzić Jan 2020

Significance Of Gravitational Nonlinearities On The Dynamics Of Disk Galaxies, Alexandre Deur, Corey Sargent, Balša Terzić

Physics Faculty Publications

The discrepancy between the visible mass in galaxies or galaxy clusters and that inferred from their dynamics is well known. The prevailing solution to this problem is dark matter. Here we show that a different approach, one that conforms to both the current standard model of particle physics and general relativity (GR), explains the recently observed tight correlation between the galactic baryonic mass and the measured accelerations in the galaxy. Using direct calculations based on GR's Lagrangian and parameter-free galactic models, we show that the nonlinear effects of GR make baryonic matter alone sufficient to explain this observation. Our approach …