On Stimulated Radiation of Black Holes

The Unruh's thermal state in the vicinity of the event horizon of the black hole provides conditions where impinging particles can radiate other particles. The subsequent decays may eventually lead to observable radiation of photons and neutrinos induced even by massive particles with gravitational interaction only. The hadronic particles will induce $\sim 30$ MeV gamma radiation from $\pi^{0}$ decays.