Constraints on ultrahigh-energy cosmic-ray sources from a search for neutrinos above 10 PeV with IceCube

TY - JOUR

T1 - Constraints on ultrahigh-energy cosmic-ray sources from a search for neutrinos above 10 PeV with IceCube

AU - Aartsen, M.G.

AU - Abraham, K.

AU - Ackermann, M.

AU - Aguilar, Juan A.

AU - Ahlers, M.

AU - Ahrens, M.

AU - Andeen, K.

AU - Anderson, T.

AU - Anton, G.

AU - Archinger, M.

AU - Arguelles, C.

AU - Axani, S.

AU - Barwick, S.W.

AU - Bay, Ryan C.

AU - Becker Tjus, J.

AU - Becker, K. H.

AU - BenZvi, S.

AU - Berghaus, P.

AU - Berley, D.

AU - Börner, M.

AU - Bose, D.

AU - Carver, T J

AU - Chirkin, D.

AU - Dumm, J. P.

AU - Ehrhardt, T.

AU - Eller, P.

AU - Evenson, P. A.

AU - Koskinen, D. Jason

AU - Larson, Michael James

AU - Medici, Morten Ankersen

AU - Rameez, M.

AU - Sarkar, Subir

AU - Hansen, E.

PY - 2016/12/7

Y1 - 2016/12/7

N2 - We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 109 GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×105 GeV to above 1011 GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×106 GeV, the highest neutrino energy observed so far, and (7.7±2.0)×105 GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

AB - We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 109 GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×105 GeV to above 1011 GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×106 GeV, the highest neutrino energy observed so far, and (7.7±2.0)×105 GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

U2 - 10.1103/physrevlett.117.241101

DO - 10.1103/physrevlett.117.241101

M3 - Journal article

C2 - 28009216

SN - 0031-9007

VL - 117

JO - Physical Review Letters

JF - Physical Review Letters

IS - 24

M1 - 241101

ER -