2025ApJ...982L..11H

The effect of tidal forces on transport within a relic accretion disk in binary black holes is studied here with a suite of two-dimensional hydrodynamic simulations. As the binary contracts owing to the emission of gravitational waves, the accretion disk is truncated, and a two-armed spiral wave is excited, which remains stationary in the rotating reference frame of the coalescing binary. Such spiral waves lead to increased transport of mass and angular momentum. Our findings suggest that even in the case of weakly ionized accretion disks spiral density waves will drain the disk long before the orbit of the two black holes decays enough for them to merge, thus dimming prospects for a detectable electromagnetic counterpart.