  Recent work, which treats the Hawking radiation as a semi-classical tunneling
process at the horizon of the Schwarzschild and Reissner-Nordstrom spacetimes,
indicates that the exact radiant spectrum is no longer pure thermal after
considering the black hole background as dynamical and the conservation of
energy. In this paper, we extend the method to investigate Hawking radiation as
massless particles tunneling across the event horizon of the Kerr black hole
and that of charged particles from the Kerr-Newman black hole by taking into
account the energy conservation, the angular momentum conservation, and the
electric charge conservation. Our results show that when self-gravitation is
considered, the tunneling rate is related to the change of Bekenstein-Hawking
entropy and the derived emission spectrum deviates from the pure thermal
spectrum, but is consistent with an underlying unitary theory.
