Minidisk Influence on Flow Variability in Accreting Spinning Black Hole Binaries: Simulations in Full General Relativity

We perform magnetohydrodynamic simulations of accreting, equal-mass binary black holes in full general relativity focusing on the effect of spin and minidisks on the accretion rate and Poynting luminosity variability. We report on the structure of the minidisks and periodicities in the mass of the minidisks, mass accretion rates, and Poynting luminosity. The accretion rate exhibits a quasi-periodic behavior related to the orbital frequency of the binary in all systems that we study, but the amplitude of this modulation is dependent on the existence of persistent minidisks. In particular, systems that are found to produce persistent minidisks have a much weaker modulation of the mass accretion rate, indicating that minidisks can increase the inflow time of matter onto the black holes, and dampen out the quasi-periodic behavior. This finding has potential consequences for binaries at greater separations where minidisks can be much larger and may dampen out the periodicities significantly.