Energies of protons accelerated in magnetospheric vacuum gaps near a black hole of mass M = 5 × 10⁹M_⊙ (left column) or 5 × 10⁸M_⊙ (right column) surrounded by RIAF with synchrotron emission spectrum peaking in the infrared at ϵ = 0.1 eV (top row) to 10^-4 eV (bottom row). Red dashed lines show the dimensionless gap height h. Green solid curves show proton energies. Dark grey parts of the diagram show the parameter range excluded by the IceCube plus Fermi data set. Green shaded areas correspond to the allowed range of parameters.