  A supermassive black hole binary may form during galaxy mergering. we
investigate the interaction of the supermassive binary black holes (SMBBHs) and
an accretion disk and show that the detected X-shaped structure in some FRII
radio galaxies may be due to the interaction-realignment of inclined binary and
accretion disk occurred within the pc scale of the galaxy center. We compare in
detail the model and observations and show that the configuration is consistent
very well with the observations of X-shaped radio sources. X-shaped radio
feature form only in FRII radio sources due to the strong interaction between
the binary and a standard disk, while the absence of X-shaped FRI radio
galaxies is due to that the interaction between the binary and the radiatively
inefficient accretion flow in FRI radio sources is negligible. It is suggested
that the binary would keep misaligned with the outer disk for most of the life
time of FRII radio galaxies and the orientation of jet in most FRII radio
galaxies distributes randomly, while the jets in most FRI radio galaxies is
expected to be vertical to the accretion disk and thus the major axis of host
galaxy. We discuss the relationship of X-shaped and double-double radio
galaxies (DDRGs). The model is applied in paticular to two X-shaped radio
sources 4C+01.30 and 3C293 and one DDRG source J0116-473 and show that the
SMBBHs in the three objects have black hole mass ratios $q \sim 0.1 - 0.3$.

Astrophysics