Circumbinary Disk Accretion into Spinning Black Hole Binaries

Abstract Supermassive black hole binaries are likely to accrete interstellar gas through a circumbinary disk. Shortly before merger, the inner portions of this disk subject general relativistic effects. To study regime, we approximate spacetime metric close orbiting holes by superimposing two boosted Kerr–Schild terms. After demonstrating quality approximation, carry out very long-term magnetohydrodynamic simulations We consider with spin dimensionless parameters magnitude 0.9, in one simulation parallel orbital angular momentum binary, but another anti-parallel. These contrasted spinless simulations. find that, for fixed surface mass density disk, aligned spins approximately reduce accretion rate 14% and counter-aligned increase it 45%, leaving many other properties unchanged.