Astrodynamics Of The Next Generation Space Weather Prediction Mission, 2019 Embry-Riddle Aeronautical University
Astrodynamics Of The Next Generation Space Weather Prediction Mission, Mark Herring
Dissertations and Theses
Accurate prediction of the solar wind properties, interplanetary magnetic field direction and various space weather phenomena becomes ever more important as our dependence on Earth orbiting spacecraft increases. Different solar wind drivers can lead both to enhancements and losses of relativistic electrons in the outer radiation belts, thus posing a major risk to satellites. To further our understanding of the Sun’s impact on the near Earth space environment, as well as to provide predictive capabilities, a mission placing monitoring satellites in key orbits in the inner Solar System is being proposed. As part of that effort, the possibility of ...
Event Reconstruction In The Advanced Particle-Astrophysics Telescope, 2019 Washington University in St. Louis
Event Reconstruction In The Advanced Particle-Astrophysics Telescope, Emily Ramey
Engineering and Applied Science Theses & Dissertations
The Advanced Particle-Astrophysics Telescope (APT) is a concept for a gamma-ray space telescope operating in the keV to MeV energy range. Due to the nature of the telescope and the physics of detection, reconstructing initial photon trajectories can be very computationally complex. This is a barrier to the real-time detection of astrophysical transient phenomena such as Gamma Ray Bursts (GRBs), and a faster reconstruction algorithm is needed in order to effectively study them. In this project, we develop such an algorithm based on Boggs & Jean (2000) and discuss the effects of certain algorithmic parameters on computational performance. For testing, we ...
Assessing & Protecting Dark Night Skies In El Morro National Monument, 2019 Utah State University
Assessing & Protecting Dark Night Skies In El Morro National Monument, Leslie Kobinsky
All Graduate Plan B and other Reports
Light pollution is causing the disappearance of dark night skies around the world. In the United States alone, 1/3 of people are unable to see the Milky Way where they live (Ramlagan, 2016). National Park Service sites contain some of the darkest skies in the country. Here at El Morro National Monument, these dark skies are a beautiful and healthy benefit to people in the local community and visitors traveling from afar. El Morro’s current park legislation does not include specific measures of protection for the night sky. This capstone project will create a baseline data set of ...
A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, 2019 Chinese Academy of Sciences
A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, Hui Sun, Ye Li, Bin-Bin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan
Physics & Astronomy Faculty Publications
Two bright X-ray transients were reported from the Chandra Deep Field South (CDF-S) archival data, namely CDF-S XT1 and XT2. Whereas the nature of the former is not identified, the latter was suggested as an excellent candidate for a rapidly spinning magnetar born from a binary neutron star (BNS) merger. Here we propose a unified model to interpret both transients within the framework of the BNS merger magnetar model. According to our picture, CDF-S XT2 is observed from the "free zone" where the magnetar spindown powered X-ray emission escapes freely, whereas CDF-S XT1 originates from the "trapped zone" where the ...
Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, 2019 The University of Texas Rio Grande Valley
Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, B. P. Abbott, Soma Mukherjee
Physics and Astronomy Faculty Publications and Presentations
The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in ...
Using Natural Phenomena To Study The Ionosphere, 2019 University of New Mexico - Main Campus
Using Natural Phenomena To Study The Ionosphere, Joseph Benjamin Malins
Physics & Astronomy ETDs
This dissertation explores novel techniques for observing the ionosphere using natural signals. The ionosphere is a region of plasma hundreds of kilometers above the Earth that affects communication and remote sensing applications across the world. Traditional techniques for observing the ionosphere involve using man made radio signals, either to reflect the signal at HF frequencies or to pass several signals through the ionosphere and compare the difference the ionosphere makes in the signals. However, such techniques are limited by the ability of equipment to produce these signals and by the numerous laws and regulations governing transmission of signals in the ...
Elaia 2019, 2019 Olivet Nazarene University
Elaia 2019, Stephen Case
Each fall, the Honors Program at Olivet Nazarene University admits a small number of academically gifted students into its freshman class. From the moment they set foot on our campus, these women and men join a community of scholars, and together they read, reflect upon, and discuss the most important ideas of the past and present—all within a Christian fellowship. The first two years of the program involve a series of Honors courses, taught by a team of faculty and modeled on the historic “old-time college,” where small class relationships, interdisciplinary discussion, and debate prevailed.
Electromagnetic Analysis Of Bidirectional Reflectance From Roughened Surfaces And Applications To Surface Shape Recovery, 2019 University of New Mexico
Electromagnetic Analysis Of Bidirectional Reflectance From Roughened Surfaces And Applications To Surface Shape Recovery, Julian Antolin Camarena
Physics & Astronomy ETDs
Scattering from randomly rough surfaces is a well-established sub area of electrodynamics. There remains much to be done since each surface and optical processes that may occur in within the scattering medium, and countless other scenarios, is different. There are also illumination models that describe lighting in a scene on the macroscopic scale where geometrical optics can be considered adequate. Of particular interest for us is the intersection of the physical scattering theories and the illumination models. We present two contributions: 1) A minimum of two independent images are needed since any opaque surface can be uniquely specified in terms ...
Secondary Infall In The Seyfert's Sextet: A Plausible Way Out Of The Short Crossing Time Paradox, 2019 University of North Dakota
Secondary Infall In The Seyfert's Sextet: A Plausible Way Out Of The Short Crossing Time Paradox, Omar López-Cruz, Héctor Javier Ibarra-Medel, Sebastián F. Sánchez, Mark Birkinshaw, Christopher Añorve, Jorge K. Barrera-Ballesteros, Jesús Falcon-Barroso, Wayne A. Barkhouse, Juan P. Torres-Papaqui
Physics Faculty Publications
We used integral field spectroscopy from CALIFA DR3 and multiwavelength publicly available data to investigate the star formation histories of galaxies in the Seyfert's Sextet (SS; HCG 79). The galaxies H79a, H79b, H79c, and H79f have low star formation rates despite showing strong signs of interaction. By exploring their individual specific star formation histories, we identified three earlier episodes of strong star formation common to these four galaxies. We use the last two episodes as markers of the epochs when the galaxies were crossing. We suggest that after the first turnaround, initially gas-rich galaxies crossed for the first time ...
High Power And Optomechanics In Advanced Ligo Detectors, 2019 Louisiana State University and Agricultural and Mechanical College
High Power And Optomechanics In Advanced Ligo Detectors, Terra Christine Hardwick
LSU Doctoral Dissertations
In September 2015, a new era of astronomy began with the first direct detection of grav- itational waves from a binary black hole coalescence. The event was captured by the Laser Interferometer Gravitational-wave Observatory, comprised of two long-baseline interferometers, one in Livingston, LA and one in Hanford, WA. At the time of the first detection, the interferometers were part way through an upgrade to an advanced configuration and were operating with a strain sensitivity of just better than 10−23/Hz1/2 around 100Hz. The full Advanced LIGO design calls for sensitivity of a few parts in 10−24 ...
Aratus: The Reverent, The Referent, 2019 Colgate University Libraries
Aratus: The Reverent, The Referent, Emily A. Wolford
Colgate Academic Review
To engage in the study of Aratus's Phaenomena is to embark upon the search to learn of Aratus the Reverent, the keeper of myths and devotee of Zeus, and Aratus, the Referent, the curator of the constellations and the preserver of the heavens.
Understanding Place Through Archaeoastronomy: A Cognitive Approach, 2019 Colgate University Libraries
Understanding Place Through Archaeoastronomy: A Cognitive Approach, Kristin V. Landau 2007
Colgate Academic Review
This investigation argues for the establishment of theoretical foundations in the field of archaeoastronomy and its implications in furthering the study and understanding of ritual and place of the ancient Maya. First, I assert that archaeoastronomy may be used as a tool in a cognitive approach to archaeology--that is, through archaeoastronomy and the study of material remains, we can understand how the Maya conceived of and thought about objects and events in their world--because the finding of archaeoastronomically significant features can strengthen previous hypotheses and add additionally evidence about how societies conceived the cosmos. Second, I assert that archaeoastronomy is ...
Alpha Capture Reaction Rates For Nucleosynthesis Within An Ab Initio Framework, 2019 Louisiana State University and Agricultural and Mechanical College
Alpha Capture Reaction Rates For Nucleosynthesis Within An Ab Initio Framework, Alison Constance Dreyfuss
LSU Doctoral Dissertations
Clustering in nuclear systems has broad impacts on all phases of stellar burning, and plays a significant role in our understanding of nucleosynthesis, or how and where nuclei are produced in the universe. The role of alpha particles in particular is extremely important for nuclear astrophysics: 4He was one of the earliest elements produced in the Big Bang, it is one of the most abundant elements in the universe, and helium burning -- in particular, the triple-alpha process -- is one of the most important ``engines'' in stars. To better understand nucleosynthesis and stellar burning, then, it is important to develop ...
#7 - Cluster Characterization And Veto Analysis Of The Frequencyhough All-Sky Continuous Gravitational Wave Search, 2019 Georgia College and State University
#7 - Cluster Characterization And Veto Analysis Of The Frequencyhough All-Sky Continuous Gravitational Wave Search, Cain Gantt, Pia Astone
Georgia Undergraduate Research Conference (GURC)
Continuous gravitational waves (CWs) can be produced by rotating neutron stars with an asymmetric mass distribution about their axis of rotation. The FrequencyHough search is an all-sky search for these signals, and the large parameter space considered introduces computational limits into the pipeline. We investigate the distributions of candidates produced by earlier stages in the pipeline, and propose the mechanisms within the pipeline that produce these effects. We also characterize the performance of two steps, a veto and ranking procedure, used to reduce the number of candidates within the FrequencyHough pipeline. We found the distance metric in the parameter space ...
Near-Resonance In A System Of Sub-Neptunes From Tess, 2019 Swarthmore College
Near-Resonance In A System Of Sub-Neptunes From Tess, S. N. Quinn, J. C. Becker, J. E. Rodriguez, S. Hadden, C. X. Huang, T. D. Morton, F. C. Adams, D. Armstrong, J. D. Eastman, J. Homer, S. R. Kane, J. J. Lissauer, J. D. Twicken, A. Vanderburg, R. Wittenmyer, G. R. Ricker, R. K. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins, E. Agol, K. Barkaoui, C. A. Beichman, F. Bouchy, L. G. Bouma, A. Burdanov, J. Campbell, R. Carlino, S. M. Cartwright, D. Charbonneau, J. L. Christiansen, D. Ciardi, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, T. Daylan, J. Dittmann, J. Doty, D. Dragomir, E. Ducrot, M. Gillon, A. Glidden, R. F. Goeke, E. J. Gonzales, K. G. Hełminiak, E. P. Horch, S. B. Howell, E. Jehin, Eric L.N. Jensen, J. F. Kielkopf, M. H. Kristiansen, N. Law, A. W. Mann, M. Marmier, R. A. Matson, E. Matthews, T. Mazeh, M. Mori, F. Murgas, C. Murray, N. Narita, L. D. Nielsen, G. Ottoni, E. Palle, R. Pawłaszek, F. Pepe, J. Pitogo De Leon, F. J. Pozuelos, H. M. Relles, J. E. Schlieder, D. Sebastian, D. Ségransan, A. Shporer, K. G. Stassun, M. Tamura, S. Udry, I. Waite, J. G. Winters, C. Ziegler
Physics & Astronomy Faculty Works
We report the Transiting Exoplanet Survey Satellite detection of a multi-planet system orbiting the V = 10.9 K0 dwarf TOI-125. We find evidence for up to five planets, with varying confidence. Three transit signals with high signal-to-noise ratio correspond to sub-Neptune-sized planets (2.76, 2.79, and 2.94 R⊕), and we statistically validate the planetary nature of the two inner planets (Pb = 4.65 days, Pc = 9.15 days). With only two transits observed, we report the outer object (P.03 = 19.98 days) as a planet candidate with high signal-to-noise ratio. We also detect a candidate ...
A Rotating Aperture Mask For Small Telescopes, 2019 California Polytechnic State University, San Luis Obispo
A Rotating Aperture Mask For Small Telescopes, Edward L. Foley
Master's Theses and Project Reports
Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that ...
Observational Studies Of Fragmentation In Molecular Clouds, 2019 University of Massachusetts Amherst
Observational Studies Of Fragmentation In Molecular Clouds, Riwaj Pokhrel, Riwaj Pokhrel, Riwaj Pokhrel
In this dissertation, I explore fragmentation physics in multiple scales in nearby molecular clouds and discuss some implications of fragmentation for cloud structure formation and star formation, primarily by analyzing multi-wavelength observations of dust emission. First, I tested the complete thermal and combined thermal and nonthermal support mechanisms that balance gravitational contraction at multiple scales in the Perseus molecular cloud. I found that the observed multiscale structures in Perseus are consistent with an inefficient thermal Jeans fragmentation, where the Jeans efficiency increases from the largest scale ($\gtrsim$10s of pc) to the smallest scale ($\sim$10s of AU). Next, I ...
The Impact Of Protostellar Feedback On Astrochemistry, 2019 University of Massachusetts Amherst
The Impact Of Protostellar Feedback On Astrochemistry, Brandt Gaches
Star formation is the lynch pin that lies in between the scales of galaxy and planet formation. Observational studies of molecular clouds, the sites of star formation, primarly use molecular line emission, providing dynamical and chemical information. Two of the key parameters of astrochemical models are far-ultraviolet (FUV) flux and the cosmic ray ionization rate. We use analytic accretion histories to predict the bolometric and FUV luminosities of protostar clusters and compare different histories with observed bolometric luminosities. We find that the Tapered Turbulent Core model best represents the observed luminosities and their dispersion. We extend the models to calculate ...
The Bivariate Luminosity-Hi Distribution Function Of Galaxies, 2019 University of Massachusetts Amherst
The Bivariate Luminosity-Hi Distribution Function Of Galaxies, Zhon Butcher
To investigate the correlation between optical luminosity and Hi mass, we obtained 21cm Hi line observations from the 100m class Nanç ay Radio Telescope of 2600 galaxies in the local universe (900 ≤ cz ≤ 12000 km s−1 ). We first present the observations and basic results of the Nanc¸ay Interstellar Baryons Legacy Extragalactic Survey (NIBLES), followed by Arecibo follow-up Hi line observations of 305 Nanç ay Hi undetected galaxies. Analysis of the low-luminosity follow-up sources indicates that they may have, on average, a more concentrated stellar mass distribution than the Nanc¸ay detected galaxies of corresponding luminosity.
Using the data ...
Nonideal Mhd Simulation Of Hl Tau Disk: Formation Of Rings, 2019 University of Nevada, Las Vegas
Nonideal Mhd Simulation Of Hl Tau Disk: Formation Of Rings, Xiao Hu, Zhaohuan Zhu, Satoshi Okuzumi, Xue-Ning Bai, Lile Wang, Kengo Tomida, James M. Stone
Physics & Astronomy Faculty Publications
Recent high-resolution observations unveil ring structures in circumstellar disks. The origin of these rings has been widely investigated under various theoretical scenarios. In this work we perform global 3D nonideal MHD simulations including effects from both ohmic resistivity and ambipolar diffusion (AD) to model the HL Tau disk. The nonideal MHD diffusion profiles are calculated based on the global dust evolution calculation including sintering effects. Disk ionization structure changes dramatically across the snow line due to the change of dust size distribution close to the snow line of major volatiles. We find that accretion is mainly driven by disk wind ...