  We show that Minkowski single-particle states localized beyond the horizon
modify the Unruh thermal distribution in an accelerated frame. This means that,
contrary to classical predictions, accelerated observers can reveal particles
emitted beyond the horizon. The method we adopt is based on deriving the
explicit Wigner characteristic function for the complete description of the
quantum field in the non-inertial frame and can be generalized to general
states.
