Interaction Of Supermassive Binary Black Holes With The Accretion Disk And Its Evolution

Supermassive binary black holes produced after galaxy mergers are the ideal lab-oratory to research general relativity.This work mainly investigates the interaction of supermassive binary black holes and circumbinary accretion disk during inspiral.First by taking into account the radiation reaction force,we derive a set of one-fluid relativistic magnetohydrodynamics(RMHD)equations with the Landau-Lifshitz ra-diation reaction force based on a relativistic two-fluid plasma.These equations could be used to situations where spatiotemporal scales of plasma's motion are sufficiently large.Then we study the evolution of accretion disk during gravitational radiation driven merger of supermassive binary black holes with an intermediate binary mass ratio and with equal mass embedded in circumbinary disk using non-relativistic hy-drodynamic simulations performed with PHANTOM.Compared with previous stud-ies using Newtonian potential,here,we adopt the post-Newtonian dynamics using the near zone metric of the binary black holes.In contrast to Newtonian poten-tial investigation,we find that there is a dramatic difference in the post-Newtonian regime,1.the secondary black hole of the binary with an intermediate binary mass ratio tends to drive the gas inside its orbit outward when adopting post-Newtonian dynamics from near zone metric,2.and the inner edge of the circumbinary accre-tion disk moving inward around the binary with equal mass falls behind that in Newtonian regime.