h1

% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Reimann:773297,
      author       = {Reimann, René},
      othercontributors = {Wiebusch, Christopher and Mertsch, Philipp},
      title        = {{S}earch for the sources of the astrophysical high-energy
                      muon-neutrino flux with the {I}ce{C}ube neutrino
                      observatory},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      reportid     = {RWTH-2019-11012},
      pages        = {1 Online-Ressource (xvii, 279 Seiten) : Illustrationen},
      year         = {2019},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University 2020; Dissertation, RWTH Aachen University, 2019},
      abstract     = {Cosmic rays have been measured for more than a century,
                      however, their sources and their acceleration process are
                      still a major open questions in astroparticle physics. Ideal
                      messenger particles and a smoking gun signal for this
                      hadronic acceleration are neutrinos. With the observation of
                      an high-energy astrophysical neutrino flux in 2013 and the
                      confirmation in the independent detection channel of
                      high-energy through-going muon-neutrinos, the IceCube
                      Neutrino Observatory opened a new window to the non-thermal
                      universe. In this thesis we search for point-like sources of
                      the observed astrophysical high-energy muon-neutrino flux.
                      The search is based on a high statistic and high purity data
                      sample taken by the IceCube Neutrino Observatory and
                      contains data from eight years of livetime. The event
                      selection focus on well-reconstructed, up- and through-going
                      muon neutrino events, which are reconstructed with a median
                      angular resolution of $\sim 1^\circ$ at 1 TeV energy and
                      $\sim 0.3^\circ$ at 1 PeV energy. An unbinned likelihood
                      method is used to test celestial positions for the existence
                      of a point-like source. The likelihood method is optimized
                      to sources showing similar characteristics as the observed
                      astrophysical high-energy muon-neutrino flux. The
                      sensitivity on the muon-neutrino flux of a point-like source
                      with an $E^{-2}$ spectrum is of the order of
                      $E^2\,\mathrm{d}N/\mathrm{d}E = 3 \cdot
                      10^{-13}\,\mathrm{TeV}\,\mathrm{cm}^{-2}\mathrm{s}^{-1}$ and
                      improves by about $\sim35\\%$ compared to previous published
                      analyses. We perform a scan of the full Northern Hemisphere
                      to search for a point-like source any where in the sky. As
                      this test suffers from the large number of tested positions,
                      in addition, sky positions from a pre-defined source list,
                      motivated by gamma-ray observations, are tested to reduce
                      the number of trials. Both test results are non significant
                      and compatible with only background. We also test for
                      neutrino emission from the source position of the blazar TXS
                      0506+056 for which a gamma-ray flare has been found in
                      spatial and temporal coincidence with a extreme-high-energy
                      neutrino alert by IceCube. This test results in a p-value of
                      2.93\% and thus is still compatible with only background. As
                      no test for a single point-like source shows a significant
                      deviation from background only, we also test for the
                      existence of a population of sub-threshold sources, both
                      using the results from the northern sky scan and the source
                      list. Therefore, we set up a population analysis, which
                      tests for an excess of small but non significant p-values.
                      Also these tests for populations of sources show no
                      significant excess above only background. Thus, exclusion
                      limits are calculated on the flux normalisation for sources
                      following a baseline $E^{-2}$ spectrum and source spectra
                      found in the literature. In addition, also exclusion limits
                      are calculated on populations of neutrino sources in
                      dependence of their effective neutrino luminosity and
                      effective source density. We conclude that rare but strong
                      sources, such as BL Lacs and FSRQs, are challenged by the
                      non observation as a significant excess in the population
                      analysis.},
      cin          = {133510 / 130000},
      ddc          = {530},
      cid          = {$I:(DE-82)133510_20140620$ / $I:(DE-82)130000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2019-11012},
      url          = {https://publications.rwth-aachen.de/record/773297},
}