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Understanding Type Ia Supernova Diversity with PHOENIX
Get PDFType Ia Supernovae (SNe Ia) are important astrophysical objects. They produce
roughly half of the iron group elements found in the universe, the energy they
release drives the evolution of galaxies, and their high
intrinsic luminosities allow them to be seen across cosmological distances.
Through the width-luminosity relation (often called the Phillips relation),
they can be used as ``standardizable candles" to serve as cosmological
distance indicators and were instrumental in the discovery of the accelerating
expansion rate of the universe. However, despite decades of detailed study,
many fundamental questions about these objects remain; including the exact
nature of their progenitor systems and the mechanism(s) by which they explode.
UV spectra are unique probe of SNe Ia physics and their evolution in throughout
the history of the universe, as much of the information about the properties of
the progenitor star and the explosion mechanism are encoded in the outer layers
of the ejecta; a region that ultraviolet spectra probe at later times than the
optical. The ultraviolet properties of SNe Ia are much more diverse than in the
optical and near infrared, and may vary with redshift. The ultraviolet
properties of SNe Ia have the ability to help us unlock their true nature; but
have historically been under-studied due to difficulties in obtaining observations
in this wavelength regime. However, recent growth in the data sets
of SNe Ia observed with the Hubble Space Telescope and the Neil Gehrels
Swift Observatory (Swift), have illuminated the need for detailed modeling
of this region in order to perform the differential comparisons necessary to
further our understanding of these objects and improve their use as cosmological
distance indicators.
In Part I, I discuss the theoretical foundations of this work. I
briefly review the important aspects of spectral formation in the ultraviolet of
SNe Ia, and introduce the two codes SYNOW and PHOENIX) used to generate
synthetic spectra of SNe Ia. I apply the spectra generated from these codes to
the UV spectra of SN~2011fe and for the first time make line identifications in
all the major ultraviolet features near maximum light, including the first ever
identifications of C IV and Si IV in a SNe Ia spectrum. Then, using
the suite of PHOENIX models, I explore the impact of luminosity variations on the
ultraviolet spectra and discuss the connections I find between the ultraviolet
and other wavelength regimes.
In Part II, I shift focus and discuss how differential comparisons in
observational studies can further our understanding of SNe Ia.
Chapter 4 details the science cases behind nearly five years of
observations using the Astrophysical Research Consortium 3.5-m telescope at Apache
Point Observatory, including highlighting instances where my observations
contributed to the advancement of our understanding of the underlying physics of
all types of supernovae and their progenitors. Chapter 5 focuses on
SN 2021fxy, a Type Ia supernovae observed extensively in multiple wavelength regimes
by the Precision Observations of Infant Supernovae (POISE) collaboration, for which
ultraviolet spectra were obtained with the Hubble Space Telescope. In
comparing SN 2021fxy to the broader sample of spectroscopically normal SNe Ia with
ultraviolet spectra from HST, I show that mid-ultraviolet flux suppression is
a common feature of SNe Ia and discuss possible mechanisms that cuase this flux
suppression and how they may be connected to different progenitors and explosion
mechanisms. Additionally, I show that SN 2021fxy is substantially similar to another
SN Ia with mid-ultraviolet suppression, SN 2017erp, and illustrate how luminosity
variations between the two SNe Ia may be responsible for the observed flux differences
between them
Aerial photo index, Muskogee County, OK. Section 11 of 15
No full textAerial photograph index (photomosaic), Muskogee Co. Okla. -AU- MAP 11 of 1
Aerial photo index, McIntosh County, OK. Section 5 of 8
No full textAerial photograph index (photomosaic), McIntosh Co. OKLA -AWJ- MAP 5 of
Aerial photo index, Muskogee County, OK. Section 12 of 15
No full textAerial photograph index (photomosaic), Muskogee Co. Okla. -AU- MAP 12 of 1
Translating the Knowledge Gap Between Researchers and Communication Designers for Improved mHealth Research
Get PDFOur industry insight focuses on the challenges for health researchers collaborating with communication designers during the development of an App for improving maternal mental health and parenting stress. We discuss the challenges around explicating and communicating tacit and domain knowledge across disciplinary boundaries. We believe this report can widen communication design’s traditional focus on users in mHealth research to consider partnerships with academic researchers. The lessons learned from our experience developing a mHealth program can be used to reduce challenges in future mHealth research, especially for collaborations between health researchers and communications designers. Considering the growth of interest in mHealth, this is extremely relevant for future team satisfaction, the optimal use of research funds and industry time, and faster development of effective mHealth tools.This is the accepted manuscript version of the following publication: Rioux, C., Weedon, S., MacKinnon, A. L., Watts, D., Salisbury, M. R., Penner-Goeke, L., Simpson, K. M., Harrington, J., Tomfohr-Madsen, L. M. & Roos, L. E. (2022). Translating the Knowledge Gap Between Researchers and Communication Designers for Improved mHealth Research. SIGDOC '22: The 40th ACM International Conference on Design of Communication, USA, 157–160. doi: 10.1145/3513130.3558997BEAM was funded by a Research Manitoba COVID-19 Rapid Response Operating Grant. CR was supported by a Postdoctoral fellowship from Research Manitoba and the Children’s Hospital Foundation of Manitoba. ALM was supported by a Social Sciences & Humanities Research Council (SSHRC) Banting Postdoctoral Fellowship (#01353-000).Ye
Phenomenology of the String Theory Landscape
Get PDFIn this dissertation, we perform a thorough phenomenological study of the string theory landscape. To this end, we compare and contrast the data collected from particle accelerators and detectors against various models of observable particle phenomena. One stark indirect evidence of underlying string theory is the existence of supersymmetric (SUSY) particles, a variety of new particles resulting from a symmetry between the bosons and fermions observed in nature: i.e. every boson should be paired with a fermionic partner and vice versa. The discovery of the Higgs boson at the LHC in 2012, the particle responsible for giving mass to matter particles (e.g. electrons) and the massive gauge bosons, has provided us with strong bounds on the masses of these yet unobserved superpartner particles, which when combined with string theory landscape arguments, can yield strong statistical predictions for observing SUSY in future upgrades to particle accelerators. Various SUSY models are explored in the context of string landscape statistics by which we can rule some models out as realistic extensions to the Standard Model (SM). We also argue how realistic SUSY models requires the Higgs boson mass to be around 125 GeV with superpartners beyond current energy limits of the LHC - just what is observed experimentally. Additionally, we also analyze the prospect of detecting dark matter particles which only gravitate and exhibit at best only weak interactions. The emergence of SUSY also equips us with such Weakly Interacting Massive Particles (WIMPs), whose mass range can then be statistically predicted using string landscape arguments
A Guided Approach to Teaching Hand Percussion Instruments in a Collegiate Applied Percussion Curriculum
No full textHand percussion is a broad term that includes many different instruments, techniques, and styles and can be difficult to decide what to include in a collegiate percussion curriculum. Although there are several resources available for most hand percussion instruments, these resources are often too large to incorporate into a collegiate curriculum, leaving the university percussion teacher to decide what information is essential. Moreover, most of the available resources only discuss how to play one hand percussion instrument which means the instructor must purchase several volumes of materials or limit the number of available options in their curriculum.
This document serves to consolidate the available resources for congas, bongos, pandeiro, tar, dumbek, and riq into a single volume and provides flexible 7-Week and 14-Week curricula for each instrument, allowing for maximum implementation based on the specific needs of a percussion program. Each curriculum will guide the student and the teacher through the basic strokes, traditional grooves, play-along assignments, and solo strategies for each drum as well as how the techniques of one hand percussion instrument can be applied to another.
This document fills a hole in the pedagogical literature by providing a concise guide to the essential skills needed for playing, teaching, and performing on congas, bongos, pandeiro, tar, dumbek, and riq
Zombie Miners: Life, Death, and Reanimation in the Wide Rural Rust Belt
No full textOver the last decade, activists and mining historians have used the concept of zombie mines to show that extractive sites have social and environmental afterlives that beckon after closure. They manifest in toxic water, air, and soil, and often in the bodies of humans and nonhuman animals long after mines’ productive lives. In this history of the Picher Field and subsequent Tar Creek Superfund site in northeastern Oklahoma, I argue that the zombie miner was an equally powerful social force. In the early twentieth century, mine operators leased Quapaw tribal land and white, native-born miners excluded Quapaw people, Black Americans, and especially immigrant labor radicals from their camps and workforce. Under “the poor man’s camp” ideal of upward mobility from worker to owner, these miners opposed labor unions and their demands for environmental and safety regulations. Guarding the poor man’s camp, they made a “white man’s camp.” And they suffered nation-leading rates of silicosis and tuberculosis. This foundation informs how this place in what I call the wide rural Rust Belt experienced the end of its industry and pursued permanence after midcentury. The memory of idealized white, hardy miners influenced how the community imagined permanence and enacted remediation of dangerous mine waste. Zombie mines and zombie miners awakened together in deindustrialization. This history moves beyond a notion that deindustrialization has a region—the Rust Belt—instead revealing a process that deeply influenced many sites of rural industry across the twentieth-century United States. This process points to the many scales at which these communities experienced deindustrialization, from bodies to the region, nation-state, and globe. An environmental history of race and labor, “Zombie Miners” illustrates the hollowness of racial exclusion as a bulwark against the ecological and economic calamities of deindustrialization
Observing System Simulation Experiments on Assimilation of Multistatic Passive Radar Network Observations into the Warn-On Forecast System to Improve Short-Term Prediction of Thunderstorm Hazards
Get PDFThe Warn-on-Forecast System (WoFS) assimilates radar and satellite observations to produce initial conditions for short-term forecasts of individual convective storms. The accuracy of the WoFS analysis is a function of the quality and number of observations assimilated. For example, Doppler radar velocity data provide useful information on the observed wind field; however, it only provides velocity observations radial to the radar beam. Recently a network of low-cost multistatic, passive radar receivers have been developed for use with the WSR-88D network. The passive radar network allows for sampling of bistatic velocities across a wide region and provides a more accurate depiction of the three-dimensional wind field in and around thunderstorms as they initiate, mature, and dissipate. Assimilation of multistatic, passive radar network observations into WoFS has the potential to improve storm-scale analyses and short-term forecasts.
This study uses Observing System Simulation Experiments (OSSEs) to assess the implications of assimilating multistatic network observations into WoFS. An OSSE was designed for a non-tornadic, hail-producing supercell that impacted northern Texas on 7 May 2020. A truth run is generated by downscaling a single real-time WoFS member forecast to 250-m horizontal grid spacing. Multistatic network observations, using six passive receivers and an emulated WSR-88D, are then created from the truth run and assimilated into the remaining WoFS members to assess the impact of these observations on the quality of WoFS analyses and forecasts of the supercell, particularly early in the storm’s life cycle. The multistatic network and the WSR-88D simulations are compared to the truth run via subjective comparisons and statistical methods. Preliminary analyses reveal minimal differences in forecast quality between the Multistatic experiment and the WSR-88D experiment; however, statistical results suggest that the WSR-88D simulation produces a slightly better forecast with higher correlation to the truth run
