Coincidence of a high-fluence blazar outburst with a PeV-energy neutrino event

Journal Article · Mon Apr 18 00:00:00 EDT 2016 · Nature Physics

DOI:https://doi.org/10.1038/nphys3715· OSTI ID:1355689

Kadler, M.; Krauß, F. ; Mannheim, K.; Ojha, R.; Müller, C.; Schulz, R.; Anton, G.; Baumgartner, W.; Beuchert, T.; Buson, S.; Carpenter, B.; Eberl, T.; Edwards, P.  G.; Eisenacher Glawion, D.; Elsässer, D.; Gehrels, N.; Gräfe, C.; Gulyaev, S.; Hase, H.; Horiuchi, S. ; James, C.  W.; Kappes, A.; Kappes, A.; Katz, U.; Kreikenbohm, A.; Kreter, M.; Kreykenbohm, I.; Langejahn, M.; Leiter, K.; Litzinger, E.; Longo, F.; Lovell, J.  E.  J.; McEnery, J.; Natusch, T.; Phillips, C.; Plötz, C.; Quick, J.; Ros, E. ; Stecker, F.  W.; Steinbring, T.; Stevens, J.; Thompson, D.  J.; Trüstedt, J.; Tzioumis, A.  K.; Weston, S.; Wilms, J.; Zensus, J.  A.

The astrophysical sources of the extraterrestrial, very high-energy neutrinos detected by the IceCube collaboration remain to be identified. Gamma-ray (γ-ray) blazars have been predicted to yield a cumulative neutrino signal exceeding the atmospheric background above energies of 100 TeV, assuming that both the neutrinos and the γ-ray photons are produced by accelerated protons in relativistic jets. As the background spectrum falls steeply with increasing energy, the individual events with the clearest signature of being of extraterrestrial origin are those at petaelectronvolt energies. Inside the large positional-uncertainty fields of the first two petaelectronvolt neutrinos detected by IceCube, the integrated emission of the blazar population has a sufficiently high electromagnetic flux to explain the detected IceCube events, but fluences of individual objects are too low to make an unambiguous source association. In this paper, we report that a major outburst of the blazar PKS B1424–418 occurred in temporal and positional coincidence with a third petaelectronvolt-energy neutrino event (HESE-35) detected by IceCube. On the basis of an analysis of the full sample of γ-ray blazars in the HESE-35 field, we show that the long-term average γ-ray emission of blazars as a class is in agreement with both the measured all-sky flux of petaelectronvolt neutrinos and the spectral slope of the IceCube signal. Finally, the outburst of PKS B1424–418 provides an energy output high enough to explain the observed petaelectronvolt event, suggestive of a direct physical association.

• Research Organization: NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. of Wurzburg (Germany)
• Sponsoring Organization: USDOE; National Aeronautics and Space Administration (NASA); German Research Foundation (DFG); German Aerospace Center (DLR) (Germany); Ministry for Education and Research (BMBF) (Germany); Helmholtz Alliance for Astroparticle Physics (HAP) (Germany); Ministry of Economy, Industry and Competitiveness (MINECO) (Spain); Generalitat Valenciana; European Cooperation in Science and Technology (COST) (Belgium)
• Contributing Organization: Fermi-LAT Collaboration
• Grant/Contract Number: NNH09ZDA001N; NNH10ZDA001N; NNH12ZDA001N; NNH13ZDA001N; WI 1860-10/1; GRK 1147; 50OR1311/50OR1303/50OR1401; 05A11WEA; 05A14WE3; AYA2012-38491-C02-01; PROMETEOII/2014/057; MP0905
• OSTI ID: 1355689
• Journal Information: Nature Physics, Vol. 12, Issue 8; ISSN 1745-2473
• Publisher: Nature Publishing Group (NPG)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
High-energy astrophysics
Particle astrophysics