Implications of Particle Acceleration in Active Galactic Nuclei for   Cosmic Rays and High Energy Neutrino Astronomy
  We consider the production of high energy neutrinos and cosmic rays in radio-quiet active galactic nuclei (AGN) or in the central regions of radio-loud AGN. We use a model in which acceleration of protons takes place at a shock in an accretion flow onto a supermassive black hole, and follow the cascade that results from interactions of the accelerated protons in the AGN environment. We use our results to estimate the diffuse high energy neutrino intensity and cosmic ray intensity due to AGN. We discuss our results in the context of high energy neutrino telescopes under construction, and measurements of the cosmic ray composition in the region of the ``knee'' in the energy spectrum at $\sim 10^7$ GeV. 
A.P. Szabo and R.J. Protheroe