- About
-
The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 1 to 2 of 2 (0.014 seconds)Spelling suggestions: "subject:"21326"" "subject:"21328""
| 1 |
UTILIZING SUPERNOVA REMNANT DYNAMICS AND ENVIRONMENTS TO PROBE CORE-COLLAPSE EXPLOSIONSJohn D Banovetz (12557977) 17 June 2022 (has links)
<p> Core-collapse supernovae are among the most consequential astronomical events. They impact galaxy evolution, chemical enrichment of the Universe, and the creation of exotic objects (e.g., black holes and neutron stars). However, aspects of supernovae such as explosion asymmetry and progenitor mass loss are not well understood. Young, nearby supernova remnants are excellent laboratories to uniquely constrain some these fundamental properties. In this thesis, I investigate two nearby oxygen-rich supernova remnants and measure the proper motion of their ejecta to estimate their center of expansions and explosion ages. These properties are important for determining central compact object ‘kick’ velocities, guiding searches for surviving companions, and creating 3D remnant reconstructions. </p>
<p><br></p>
<p>I estimate the center of expansion and age of two supernova remnants, 1E0102.2-7219 (E0102) and N132D utilizing two epochs of Hubble Space Telescope imaging to measure the proper motion of their ejecta. For E0102, the proper motions show evidence for a nonhomologous expansion, which combined with spectral observations, support the idea that this remnant is expanding into an asymmetric circumstellar environment. Using the new proper-motion derived age and center of expansion, I provide a new ‘kick’ velocity estimate for E0102’s candidate neutron star. For N132D, I measure the proper motion of the ejecta both visually and using a novel computer vision procedure which identifies and measures the proper motions of the knots. I find that N132D’s ejecta are still ballistic, along with evidence of explosion asymmetry. My results represent the first proper-motion derived center of expansion and age of N132D. </p>
<p><br></p>
<p>Finally, I investigate diffuse interstellar bands observed towards progenitor candidates of core-collapse supernovae to test whether time variability can be a possible probe of the mass loss and surrounding environments of these systems. I find evidence of time variability in diffuse interstellar band carriers located in two of these environments. This is especially unusual as diffuse interstellar bands are normally attributed to the interstellar medium. These findings imply that the sources of these bands are closer to the stellar objects than previously thought and can provide insight into the currently unknown sources of diffuse interstellar bands. </p>
|
| 2 |
Implementation and Analysis of Co-Located Virtual Reality for Scientific Data VisualizationJordan M McGraw (8803076) 07 May 2020 (has links)
<div>Advancements in virtual reality (VR) technologies have led to overwhelming critique and acclaim in recent years. Academic researchers have already begun to take advantage of these immersive technologies across all manner of settings. Using immersive technologies, educators are able to more easily interpret complex information with students and colleagues. Despite the advantages these technologies bring, some drawbacks still remain. One particular drawback is the difficulty of engaging in immersive environments with others in a shared physical space (i.e., with a shared virtual environment). A common strategy for improving collaborative data exploration has been to use technological substitutions to make distant users feel they are collaborating in the same space. This research, however, is focused on how virtual reality can be used to build upon real-world interactions which take place in the same physical space (i.e., collaborative, co-located, multi-user virtual reality).</div><div><br></div><div>In this study we address two primary dimensions of collaborative data visualization and analysis as follows: [1] we detail the implementation of a novel co-located VR hardware and software system, [2] we conduct a formal user experience study of the novel system using the NASA Task Load Index (Hart, 1986) and introduce the Modified User Experience Inventory, a new user study inventory based upon the Unified User Experience Inventory, (Tcha-Tokey, Christmann, Loup-Escande, Richir, 2016) to empirically observe the dependent measures of Workload, Presence, Engagement, Consequence, and Immersion. A total of 77 participants volunteered to join a demonstration of this technology at Purdue University. In groups ranging from two to four, participants shared a co-located virtual environment built to visualize point cloud measurements of exploded supernovae. This study is not experimental but observational. We found there to be moderately high levels of user experience and moderate levels of workload demand in our results. We describe the implementation of the software platform and present user reactions to the technology that was created. These are described in detail within this manuscript.</div>
|
Page generated in 0.0186 seconds