Circumbinary discs from tidal disruption events

Tidal disruption events, which occur when a star is shredded by the tidal field of a supermassive black hole (SMBH), provide a means of fuelling black hole accretion. Here we show, using a combination of three-body orbit integrations and hydrodynamic simulations, that these events are also capable of generating circumbinary rings of gas around tight SMBH binaries with small mass ratios. Depending on the thermodynamics, these rings can either fragment into clumps that orbit the binary, or evolve into a gaseous circumbinary disc. We argue that tidal disruptions provide a direct means of generating circumbinary discs around SMBH binaries and, more generally, can replenish the reservoir of gas on very small scales in galactic nuclei.