Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Linking high-energy cosmic particles by black-hole jets embedded in large-scale structures


The origin of ultrahigh-energy cosmic rays (UHECRs) is a half-century-old enigma1. The mystery has been deepened by an intriguing coincidence: over ten orders of magnitude in energy, the energy generation rates of UHECRs, PeV neutrinos and isotropic sub-TeV γ-rays are comparable, which hints at a grand unified picture2. Here we report that powerful black hole jets in aggregates of galaxies can supply the common origin for all of these phenomena. Once accelerated by a jet, low-energy cosmic rays confined in the radio lobe are adiabatically cooled; higher-energy cosmic rays leaving the source interact with the magnetized cluster environment and produce neutrinos and γ-rays; the highest-energy particles escape from the host cluster and contribute to the observed cosmic rays above 100 PeV. The model is consistent with the spectrum, composition and isotropy of the observed UHECRs, and also explains the IceCube neutrinos and the non-blazar component of the Fermi γ-ray background, assuming a reasonable energy output from black hole jets in clusters.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Get just this article for as long as you need it


Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Extragalactic multi-messenger (UHECR, high-energy neutrino and γ-ray) background spectra.
Fig. 2: Mean of the maximum depth of an air shower of UHECRs.


  1. Linsley, J. Evidence for a primary cosmic-ray particle with energy 1020 eV. Phys. Rev. Lett. 10, 146–148 (1963).

    Article  ADS  Google Scholar 

  2. Murase, K. & Waxman, E. Constraining high-energy cosmic neutrino sources: Implications and prospects. Phys. Rev. D 94, 103006 (2016).

    Article  ADS  Google Scholar 

  3. Hillas, A. M. The origin of ultra-high-energy cosmic rays. Ann. Rev. Astron. Astrophys. 22, 425–444 (1984).

    Article  ADS  Google Scholar 

  4. Aab, A. et al. Contributions to the 34th International Cosmic Ray Conference. in Proc. Sci. (ICRC 2015) (2015).

  5. Charles, J. et al. Summary of results from the Telescope Array Experiment. in Proc. Sci. (ICRC2015) 035 (2015).

  6. Halzen, F. High-energy neutrino astrophysics. Nat. Phys. 13, 232–238 (2016).

    Article  Google Scholar 

  7. Aartsen, M. et al. First observation of PeV-energy neutrinos with IceCube. Phys. Rev. Lett. 111, 021103 (2013).

    Article  ADS  Google Scholar 

  8. Aartsen, M. G. et al. Observation and characterization of a cosmic muon neutrino flux from the northern hemisphere using six years of IceCube data. Astrophys. J. 833, 3–21 (2016).

    Article  ADS  Google Scholar 

  9. Aartsen, M. G. et al. Observation of astrophysical neutrinos in six years of IceCube data. in Proc. Sci. (ICRC2017) 981 (2017).

  10. Murase, K., Inoue, S. & Nagataki, S. Cosmic rays above the second knee from clusters of galaxies and associated high-energy neutrino emission. Astrophys. J. 689, L105–L108 (2008).

    Article  ADS  Google Scholar 

  11. Kotera, K. et al. Propagation of ultrahigh energy nuclei in clusters of galaxies: resulting composition and secondary emissions. Astrophys. J. 707, 370–386 (2009).

    Article  ADS  Google Scholar 

  12. Loeb, A. & Waxman, E. The cumulative background of high energy neutrinos from starburst galaxies. J. Cosmol. Astropart. Phys. 0605, 003 (2006).

    Article  ADS  Google Scholar 

  13. Murase, K., Ahlers, M. & Lacki, B. C. Testing the hadronuclear origin of PeV neutrinos observed with IceCube. Phys. Rev. D 88, 121301 (2013).

    Article  ADS  Google Scholar 

  14. Ackermann, M. et al. The spectrum of isotropic diffuse gamma-ray emission between 100 MeV and 820 GeV. Astrophys. J. 799, 86–110 (2015).

    Article  ADS  Google Scholar 

  15. Ackermann, M. et al. Resolving the extragalactic γ -ray background above 50 GeV with the fermi large area telescope. Phys. Rev. Lett. 116, 151105 (2016).

    Article  ADS  Google Scholar 

  16. Apel, W. D. et al. KASCADE-grande measurements of energy spectra for elemental groups of cosmic rays. Astropart. Phys. 47, 54–66 (2013).

    Article  ADS  Google Scholar 

  17. Buitink, S. et al. A large light-mass component of cosmic rays at 1017–1017.5 eV from radio observations. Nature 531, 70–73 (2016).

    Article  ADS  Google Scholar 

  18. Aartsen, M. G. et al. Constraints on ultrahigh-energy cosmic-ray sources from a search for neutrinos above 10 PeV with IceCube. Phys. Rev. Lett. 117, 241101 (2016).

    Article  ADS  Google Scholar 

  19. Murase, K., Dermer, C. D., Takami, H. & Migliori, G. Blazars as ultra-high-energy cosmic-ray sources: implications for TeV gamma-ray observations. Astrophys. J. 749, 63–78 (2012).

    Article  ADS  Google Scholar 

  20. Kaiser, C. R. & Best, P. N. Luminosity function, sizes and FR dichotomy of radio-loud AGN. Mon. Not. R. Astron. Soc. 381, 1548–1560 (2007).

    Article  ADS  Google Scholar 

  21. Kataoka, J. & Stawarz, Ł. X-ray emission properties of large-scale jets, hot spots, and lobes in active galactic nuclei. Astrophys. J. 622, 797–810 (2005).

    Article  ADS  Google Scholar 

  22. Bordas, P., Bosch-Ramon, V. & Perucho, M. The evolution of the large-scale emission in Fanaroff-Riley type I jets. Mon. Not. R. Astron. Soc. 412, 1229–1236 (2011).

    ADS  Google Scholar 

  23. Best, P. N., von der Linden, A., Kauffmann, G., Heckman, T. M. & Kaiser, C. R. On the prevalence of radio-loud active galactic nuclei in brightest cluster galaxies: implications for AGN heating of cooling flows. Mon. Not. R. Astron. Soc. 379, 894–908 (2007).

    Article  ADS  Google Scholar 

  24. Brunetti, G. & Jones, T. W. Cosmic rays in galaxy clusters and their nonthermal Emission. Int. J. Mod. Phys. D 23, 1430007–1430098 (2014).

    Article  ADS  Google Scholar 

  25. Zandanel, F., Tamborra, I., Gabici, S. & Ando, S. High-energy gamma-ray and neutrino backgrounds from clusters of galaxies and radio constraints. Astron. Astrophys. 578, 1–13 (2015).

    Article  Google Scholar 

  26. Ma, C.-J., McNamara, B. R., Nulsen, P. E. J., Schaffer, R. & Vikhlinin, A. Average heating rate of hot atmospheres in distant clusters by radio active galactic nucleus: evidence for continuous active galactic nucleus heating. Astrophys. J. 740, 51–61 (2011).

    Article  ADS  Google Scholar 

  27. Abreu, P. et al. Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory. J. Cosmol. Astropart. Phys. 1305, 009 (2013).

    Google Scholar 

  28. Verzi, V., Ivanov, D. & Tsunesada, Y. Measurement of energy spectrum of ultra-high energy cosmic rays. Preprint at (2017).

  29. Murase, K. & Beacom, J. F. Neutrino background flux from sources of ultrahigh-energy cosmic-ray nuclei. Phys. Rev. D 81, 123001 (2010).

    Article  ADS  Google Scholar 

  30. De Domenico, M., Settimo, M., Riggi, S. & Bertin, E. Reinterpreting the development of extensive air showers initiated by nuclei and photons. J. Cosmol. Astropart. Phys. 1307, 050 (2013).

    Article  ADS  Google Scholar 

Download references


We thank R. Alves Batista, M. Bustamante, M. Coleman Miller, C. Reynolds and M. Unger for helpful comments. This work made use of supercomputing resources at the University of Maryland. We gratefully acknowledge support from the Eberly College of Science of Penn State University and the Institute for Gravitation and the Cosmos. The work of K.M. is supported by Alfred P. Sloan Foundation and NSF grant No. PHY-1620777.

Author information

Authors and Affiliations



K.F. performed simulations and produced the figures. K.M. designed the research and contributed to the calculations. Both authors edited the manuscript.

Corresponding author

Correspondence to Kohta Murase.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Supplementary Information

Supplementary Information

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Fang, K., Murase, K. Linking high-energy cosmic particles by black-hole jets embedded in large-scale structures. Nature Phys 14, 396–398 (2018).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing