Non-thermal emission from fall-back clouds in the Broad-Line Region of
  Active Galactic Nuclei
  The spectra of active galactic nuclei exhibit broad-emission lines that
presumably originate in the Broad-Line Region (BLR) with gaseous-dusty clouds
in a predominantly Keplerian motion around the central black hole. Signatures
of both inflow and outflow motion are frequently seen. The dynamical character
of BLR is consistent with the scenario that has been branded as the Failed
Radiatively Accelerated Dusty Outflow (FRADO; Czerny & Hryniewicz 2011). In
this scheme, frequent high-velocity impacts of BLR clouds falling back onto the
underlying accretion disk are predicted. The impact velocities depend mainly on
the black-hole mass, accretion rate, and metallicity and they range from a few
km s$^{-1}$ up to thousands of km s$^{-1}$. Formation of strong shocks due to
the collisions can give rise to the production of relativistic particles and
associated radiation signatures. In this work, the non-thermal radiation
generated in this process is investigated, and the spectral energy
distributions for different parameter sets are presented. We find that the
non-thermal processes caused by the impacts of clouds can lead to emission in
the X-ray and the gamma-ray bands, playing the cloud density and metallicity a
key role.
