On the propagation of gravitational waves in strong magnetic fields
  The propagation of gravitational waves is explored in the cosmological
context. It is explicitly demonstrated that the propagation of gravitational
waves could be influenced by the medium. It is shown that in the thermal
radiation, the propagation of gravitational waves in general relativity is
different from that in the scalar-tensor theory. The propagation of
gravitational waves is investigated in the uniform magnetic field. As a result,
it is found that cosmic magnetic fields could influence on the propagation of
gravitational waves to non-negligible extent. The corresponding estimation for
the spiral galaxy NGC 6946 effect is made.
