engWirtz, MarcusErdmann, MartinHebbeker, ThomasSearch for signatures of cosmic-ray deflection induced by magnetic fields with the Pierre Auger Observatoryinfo:eu-repo/classification/ddc/530arrival directionscosmic-ray sourcesgalactic magnetic fieldultra-high energy cosmic raysTwo analysis approaches are presented to search for signatures of ultra-high energy cosmic-ray deflection induced by cosmic magnetic fields. The first analysis is based on a classical principal component analysis of the arrival-direction distribution within a circular region of the sky. The major- and minor axes of the eigenvectors tangentially to the local celestial sphere are used to build an observable which is sensitive to the elongation of the event distribution within the region. In the second analysis, the orientation of deflection patterns is parameterized by a spherical harmonics expansion and optimized by a gradient-descent based fit using a likelihood-ratio approach. Here, an elongated event excess in the vicinity of each cosmic ray is evaluated by employing an elliptically-shaped probability density function where the major axis is aligned with the prediction from the spherical harmonics. To state an expected sensitivity, an astrophysical simulation software for an universe with arbitrary spatial distribution of sources featuring a rigidity-based acceleration mechanism was developed in this work. Both analyses are applied to data of the Pierre Auger Observatory with energies above 20 EeV and 40 EeV, respectively. While in the first analysis the resulting response on data is entirely compatible with the isotropic null-hypothesis, the outcome of the second analysis is only achieved by 0.11% of the isotropic realizations of the sky. After the penalization for a scan of the ellipse geometry, the post-trial isotropic chance probability is about 1.76%. The most significant pattern was found at Galactic coordinates of (l, b) = (−60°, -5°), which might well be explained by cosmic-ray events originating from the active galactic nucleus Centaurus A or the starburst galaxy NGC 4945.Aachen : RWTH Aachen University 1 Online-Ressource (187 Seiten) : Illustrationen, Diagramme (2020). doi:10.18154/RWTH-2020-12558 = Dissertation, RWTH Aachen University, 2020info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionRWTH Aachen University2020info:eu-repo/semantics/openAccessDEhttps://publications.rwth-aachen.de/record/809345https://publications.rwth-aachen.de/search?p=id:%22RWTH-2020-12558%22StudentsStudent Financial Aid ProvidersTeachersResearchersinfo:eu-repo/semantics/altIdentifier/doi/10.18154/RWTH-2020-12558