High-energy neutrinos from active galactic nuclei

We calculate the spectrum and high-energy ν background flux from photomeson production in active galactic nuclei (AGN), using the recent UV and x-ray observations to define the photon fields and an accretion-disk shock-acceleration model for producing high-energy particles. Collectively, AGN produce the dominant isotropic ν background between ${10}^4$ and ${10}^{10}$ GeV, detectable with current instruments. AGN ν’s should produce a sphere of stellar disruption which may explain the ‘‘broad-line region’’ seen in AGN.