TeV signatures of compact UHECR accelerators

We study numerically particle acceleration by the electric field induced near the horizon of a rotating supermassive black hole embedded in a uniform magnetic field. We find that acceleration of protons to energy 10^{20} eV is possible only at extreme values of parameters. We also find that the acceleration is very inefficient and is accompanied by TeV radiation whose total power exceeds at least by a factor of 1000 the total power emitted in ultra-high energy cosmic rays (UHECR). This implies that if the observed UHECR with energy >10^{20} eV were produced by O(10) sources situated within 50 Mpc, each of them would overshine Crab nebula by more than two orders of magnitude. Recent TeV observations exclude this possibility. A model in which O(100) sources are situated at 100-1000 Mpc is not ruled out and can be experimentally tested by present TeV gamma-ray telescopes. Such a model can explain the observed UHECR flux at moderate energies (4-5)x10^{19} eV.