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Published October 2024 | Version Published
Journal Article Open

Association of the IceCube neutrinos with blazars in the CGRaBS sample

Creators

  • 1. ROR icon University of Turku
  • 2. ROR icon Aalto University
  • 3. ROR icon Marshall Space Flight Center
  • 4. ROR icon Norwegian University of Science and Technology
  • 5. ROR icon University of Crete
  • 6. ROR icon University of Chile
  • 7. ROR icon California Institute of Technology
  • 8. ROR icon University of Concepción
  • 9. ROR icon Ruhr University Bochum

Abstract

The origin of high-energy (HE) astrophysical neutrinos has remained an elusive hot topic in the field of HE astrophysics for the past decade. Apart from a handful of individual associations, the vast majority of HE neutrinos arise from unknown sources. While there are theoretically motivated candidate populations, such as blazars – a subclass of active galactic nuclei with jets pointed toward our line of sight – they have not been convincingly linked to HE neutrino production yet. Here, we perform a spatio-temporal association analysis between a sample of blazars (from the CGRaBS catalog) in the radio and optical bands and the most up-to-date IceCube HE neutrino catalog. We find that if the IceCube error regions are enlarged by 1° in quadrature, to account for unknown systematic errors at a maximal level, a spatio-temporal correlation between the multiwavelength light curves of the CGRaBS blazars and the IceCube HE neutrinos is hinted at, least at a 2.17σ significance level. On the other hand, when the IceCube error regions are taken as their published values, we do not find any significant correlations. A discrepancy in the blazar-neutrino correlation strengths, when using such minimal and enlarged error region scenarios, was also obtained in a recent study by the IceCube collaboration. In our study, this difference arises because several flaring blazars – coinciding with a neutrino arrival time – happen to narrowly miss the published 90%-likelihood error region of the nearest neutrino event. For all of the associations driving our most significant correlations, the flaring blazar is much less than 1° away from the published error regions. Therefore, our results indicate that the question of the blazar-neutrino connection is highly sensitive to the reconstruction of the neutrino error regions, whose reliability is expected to improve with the next generation of neutrino observatories.

Copyright and License

© The Authors 2024. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Acknowledgement

P.K. was supported by Academy of Finland projects 346071 and 345899. E.L. was supported by Academy of Finland projects 317636, 320045, and 346071. T.H. was supported by Academy of Finland projects 317383, 320085, 322535, and 345899. J.J. was supported by Academy of Finland projects 320085 and 345899. K.K. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 101002352). S.K. acknowledges support from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme under grant agreement No. 771282. R.R. is supported by ANID BASAL grant FB210003. W.M. gratefully acknowledges support by the ANID BASAL project FB210003 and FONDECYT 11190853. The OVRO 40 m program was supported by NASA grants NNG06GG1G, NNX08AW31G, NNX11A043G, and NNX13AQ89G from 2006 to 2016 and NSF grants AST-0808050, and AST-1109911 from 2008 to 2014, along with private funding from Caltech and the MPIfR. Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Grant No. AST-2034437 and a collaboration including Caltech, IPAC, the Weizmann Institute for Science, the Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan, the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore National Laboratories, and IN2P3, France. Operations are conducted by COO, IPAC, and UW. The ZTF forced-photometry service was funded under the Heising-Simons Foundation grant #12540303 (PI: M.J.Graham). This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile. This work has made use of data from the Joan Oró Telescope (TJO) of the Montsec Observatory (OdM), which is owned by the Catalan Government and operated by the Institute for Space Studies of Catalonia (IEEC). We additionally thank Konstancja Satalecka and Simone Garrappa for their insightful comments when handling the IceCube neutrino events.

Data Availability

This paper is accompanied by three tables Neut.dat, Blz.dat, and Assoc.dat which are available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A111

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Additional details

Related works

Is new version of
Discussion Paper: arXiv:2407.07153 (arXiv)
Is supplemented by
Dataset: https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/690/A111 (URL)

Funding

Research Council of Finland
346071
Research Council of Finland
345899
Research Council of Finland
317636
Research Council of Finland
320045
Research Council of Finland
317383
Research Council of Finland
320085
Research Council of Finland
322535
European Research Council
101002352
European Research Council
771282
Agencia Nacional de Investigación y Desarrollo
FB210003
Fondo Nacional de Desarrollo Científico y Tecnológico
11190853
National Aeronautics and Space Administration
NNG06GG1G
National Aeronautics and Space Administration
NNX08AW31G
National Aeronautics and Space Administration
NNX11A043G
National Aeronautics and Space Administration
NNX13AQ89G
National Science Foundation
AST-0808050
National Science Foundation
AST-1109911
National Science Foundation
AST-2034437
Heising-Simons Foundation
12540303
National Aeronautics and Space Administration
NN12AR55G
National Aeronautics and Space Administration
80NSSC18K0284
National Aeronautics and Space Administration
80NSSC18K1575
National Aeronautics and Space Administration
Kepler/K2 J1944/80NSSC19K011
National Aeronautics and Space Administration
HST GO-15889
Science and Technology Facilities Council
ST/T000198/1
Science and Technology Facilities Council
ST/S006109/1

Dates

Accepted
2024-07-09
Available
2024-10-03
Published online

Caltech Custom Metadata

Caltech groups
Astronomy Department, Owens Valley Radio Observatory, Division of Physics, Mathematics and Astronomy (PMA)
Publication Status
Published