https://doi.org/10.1140/epjc/s10052-019-6680-0
Regular Article - Experimental Physics
Search for steady point-like sources in the astrophysical muon neutrino flux with 8 years of IceCube data
1
III. Physikalisches Institut, RWTH Aachen University, 52056, Aachen, Germany
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Department of Physics, University of Adelaide, Adelaide, 5005, Australia
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Department of Physics and Astronomy, University of Alaska Anchorage, 3211 Providence Dr., Anchorage, AK, 99508, USA
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Department of Physics, University of Texas at Arlington, 502 Yates St., Science Hall Rm 108, Box 19059, Arlington, TX, 76019, USA
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CTSPS, Clark-Atlanta University, Atlanta, GA, 30314, USA
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School of Physics and Center for Relativistic Astrophysics, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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Department of Physics, Southern University, Baton Rouge, LA, 70813, USA
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Department of Physics, University of California, Berkeley, CA, 94720, USA
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Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
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Institut für Physik, Humboldt-Universität zu Berlin, 12489, Berlin, Germany
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Fakultät für Physik & Astronomie, Ruhr-Universität Bochum, 44780, Bochum, Germany
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Science Faculty CP230, Université Libre de Bruxelles, 1050, Brussels, Belgium
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Dienst ELEM, Vrije Universiteit Brussel (VUB), 1050, Brussels, Belgium
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Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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Department of Physics and Institute for Global Prominent Research, Chiba University, Chiba, 263-8522, Japan
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Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
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Department of Physics, University of Maryland, College Park, MD, 20742, USA
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Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH, 43210, USA
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Department of Astronomy, Ohio State University, Columbus, OH, 43210, USA
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Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
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Department of Physics, TU Dortmund University, 44221, Dortmund, Germany
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Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA
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Department of Physics, University of Alberta, Edmonton, Alberta, T6G 2E1, Canada
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Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058, Erlangen, Germany
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Département de Physique Nucléaire et Corpusculaire, Université de Genève, 1211, Geneva, Switzerland
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Department of Physics and Astronomy, University of Gent, 9000, Gent, Belgium
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Department of Physics and Astronomy, University of California, Irvine, CA, 92697, USA
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Department of Physics and Astronomy, University of Kansas, Lawrence, KS, 66045, USA
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SNOLAB, 1039 Regional Road 24, Creighton Mine 9, Lively, ON, P3Y 1N2, Canada
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Department of Physics and Astronomy, UCLA, Los Angeles, CA, 90095, USA
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Department of Astronomy, University of Wisconsin, Madison, WI, 53706, USA
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Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI, 53706, USA
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Institute of Physics, University of Mainz, Staudinger Weg 7, 55099, Mainz, Germany
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Department of Physics, Marquette University, Milwaukee, WI, 53201, USA
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Physik-Department, Technische Universität München, 85748, Garching, Germany
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Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, 48149, Münster, Germany
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Department of Physics and Astronomy, Bartol Research Institute, University of Delaware, Newark, DE, 19716, USA
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Department of Physics, Yale University, New Haven, CT, 06520, USA
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Department of Physics, University of Oxford, 1 Keble Road, Oxford, OX1 3NP, UK
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Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA
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Physics Department, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA
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Department of Physics, University of Wisconsin, River Falls, WI, 54022, USA
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Department of Physics and Astronomy, University of Rochester, Rochester, NY, 14627, USA
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Department of Physics, Oskar Klein Centre, Stockholm University, 10691, Stockholm, Sweden
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Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY, 11794-3800, USA
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Department of Physics, Sungkyunkwan University, Suwon, 440-746, Korea
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Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL, 35487, USA
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Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA, 16802, USA
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Department of Physics, Pennsylvania State University, University Park, PA, 16802, USA
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Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Uppsala, Sweden
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Department of Physics, University of Wuppertal, 42119, Wuppertal, Germany
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DESY, 15738, Zeuthen, Germany
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https://icecube.wisc.edu/
* e-mail: analysis@icecube.wisc.edu
Received:
19
November
2018
Accepted:
13
February
2019
Published online:
13
March
2019
The IceCube Collaboration has observed a high-energy astrophysical neutrino flux and recently found evidence for neutrino emission from the blazar TXS 0506056. These results open a new window into the high-energy universe. However, the source or sources of most of the observed flux of astrophysical neutrinos remains uncertain. Here, a search for steady point-like neutrino sources is performed using an unbinned likelihood analysis. The method searches for a spatial accumulation of muon-neutrino events using the very high-statistics sample of about 497,000 neutrinos recorded by IceCube between 2009 and 2017. The median angular resolution is
at 1 TeV and improves to
for neutrinos with an energy of 1 PeV. Compared to previous analyses, this search is optimized for point-like neutrino emission with the same flux-characteristics as the observed astrophysical muon-neutrino flux and introduces an improved event-reconstruction and parametrization of the background. The result is an improvement in sensitivity to the muon-neutrino flux compared to the previous analysis of
assuming an
spectrum. The sensitivity on the muon-neutrino flux is at a level of
. No new evidence for neutrino sources is found in a full sky scan and in an a priori candidate source list that is motivated by gamma-ray observations. Furthermore, no significant excesses above background are found from populations of sub-threshold sources. The implications of the non-observation for potential source classes are discussed.
© The Author(s), 2019