Prompt Shocks in the Gas Disk Around a Recoiling Supermassive Black Hole Binary

Understand

Supermassive black hole binaries (BHBs) produced in galaxy mergers recoil at the time of their coalescence due to the emission of gravitational waves (GWs).

• We simulate the response of a thin, 2D disk of collisionless particles, initially on circular orbits around a 10^6 M_sun BHB, to kicks that are either parallel or perpendicular to the initial orbital plane.
• Typical kick velocities (v_k) can exceed the sound speed in a circumbinary gas disk.
• While the inner disk is strongly bound to the recoiling binary, the outer disk is only weakly bound or unbound.