Истомин Яков Николаевич   (ФИАН)

Acceleration of particles in the vicinity of a massive black hole

We propose a two-step mechanism for charged particle acceleration in the magnetosphere of a massive black hole surrounded by an accretion disk. Particles first gain energy by stochastic process during the accretion phase. It is shown that effective proton acceleration up to energies  eV is possible in the turbulent magnetized accretion disk. The distribution function of energetic protons over energies is a power law function with typical index . Here electrons are not very efficiently accelerated because of their drastic losses by synchrotron radiation. In a second time, part of the fast particles escape from the disk and are then entrained by the magnetic structure above the disk, in the rotating black hole magnetosphere. They thus gain additional energy by direct centrifugal mechanism, up to about for the protons and to 10-100 TeV for the electrons when they cross the light cylinder surface. Such energetic particles can further radiate in the TeV spectral range observed by Cherenkov experiments as HESS and MAGIC. Energetic protons can produce -radiation in the energy band and above mainly by nuclei collisions with the disk matter, clouds, or ambient low energy photons.