Interaction of eccentric supermassive binary black hole with intermediate mass ratio and circumbinary accretion disk (2312.15461v1)

Abstract: 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.