  Recent simulations show that the eccentricity of supermassive binary black
hole with intermediate mass ratio could grow toward near unity through
gravitational interaction with the stellar background in the merging remnant
after two galaxies merge. The increased eccentricity reduces the timescale of
the supermassive binary black hole merger through the strong gravitational
radiation at periastron. Usually, large amount of gas flows toward the center
of the newly merged galaxy, forming circumbinary gaseous disk around the binary
in the center of the newly merged galaxy. Tidal interaction between such
eccentric binary with intermediate mass ratio and circumbinary disk need to be
investigated quantitatively. In this work, we study the gravitational
interaction of the eccentric supermassive binary black hole with intermediate
mass ratio and the circumbinary disk using code FARGO3D. Simulations are
carried out with different semimajor, eccentricity and mass ratio. We find that
the accretion rate onto the inner boundary could be strongly affected by the
secondary black hole and tend to present periodic accretion rate in some
situations. Such periodic accretion rate can be used as electromagnetic
counterpart to the gravitational wave radiated by such kind of eccentric
binary.
