Project Description:

This project aims towards probing the relativistic particle content of the most numerous, persistent population of high energy cosmic sources in the Universe: jets of active galactic nuclei (AGN). This undertaking is leveraged by today's synergy of high performance ground- and space-based photon detecting instruments as well as key advances in astroparticle physics experiments, yielding dense high quality data over a broad energy range from a large collection of AGN. Such powerful objects are among the prime candidate sources of the enigmatic ultrahigh energy cosmic rays, however, conclusive evidence is still missing. We aim to develop diagnostic tools that probe the composition of the material in AGN jets, and allows a systematic search for observational features of hadronic interactions from high energy cosmic jet sources. Meaningful constraints on their relativistic particle content will have far-reaching implications for the physics of cosmic rays, particle acceleration to energies beyond reach for any terrestrial laboratory, and our physical understanding of jet formation, collimation and mass loading.
We also expect impact for searches of extragalactic neutrino sources.

This research is supported by a Marie Curie International Reintegration Grant (grant 24803) within the 7th European Community Framework Programme.



  • Assoc.-Prof. Dr. Anita Reimer (lead)
  • Institut für Theoretische Physik, and
    Institut für Astro- und Teilchenphysik
    Leopold-Franzens-Universität Innsbruck
    Technikerstr. 25
    6020 Innsbruck
    Phone: +43-512-507-52274
    E-mail: anita.reimer(at)

  • Assoc.-Prof. Dr. Raymond Protheroe
  • School of Chemistry and Physics
    The University of Adelaide
    North Terrace
    E-mail: raymond.protheroe(at)


  • Lars Hunger
  • Dimitar Vlaykov
  • Thomas Kittl
  • Klaus Reitberger

  • Project Tools:

  • High Energy Radiation Transport Code

  • Project Data Base:

    Source modeling results:

    Related publications

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