The origins and compositions of ultra-high energy cosmic rays (UHECR) remains a mystery to this day. The Pierre Auger Observatory (PAO) is being constructed now in the hopes that it will help solve this mystery by detecting more UHECR than any previous experiment. In this dissertation, I will discuss this experiment, and analyze the data collected so far by comparing it with simulated data from possible source distributions. In these simulations, I will track antiprotons, along with other possible cosmic ray primaries, through various models of galactic and extragalactic magnetic fields. Once they reach a certain distance, I will record their positions on the sky. These final positions will determine the weight of that position on the sky. This weight will then be applied to possible source distributions, and the particles will be reinjected back to the earth's surface, and the simulated arrival directions will be analyzed. I will be using the method of calculating spherical harmonics coefficients to analyze the data. The method of using these angular power spectra is an attempt to provide a common language for model builders and experimentalists. Anisotropies of any size are easily detected using these coefficients, making them an ideal way to look at observed events that might not be coming from single, point sources. I will compare the results of this analysis with data obtained by the PAO by calculating spherical harmonics coefficients. After comparing the events collected to date by the PAO with three possible source distributions-isotropic, Active Galactic Nuclei, and nearby galaxies-I have observed that the data looks consistent with either nearby galaxies or AGNs as sources. However, there does exist an extra dipole moment inherent to a half-sky exposure, such as the PAO currently has, which adds in an uncertainty that fundamentally undermines the capabilities of large-scale anisotropy analysis. In the absence of clear point-like sources, construction of a detector in the Northern hemisphere will be necessary in order to know the origins of UHECRs with any confidence.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-08302007-084124 |
| Date | 05 September 2007 |
| Creators | McEwen, Megan Alicia |
| Contributors | James Matthews, Hsiao-Chun Wu, Kip Matthews, Juhan Frank, Joel Tohline |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-08302007-084124/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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