Circumbinary discs from tidal disruption events

TL;DR

This paper demonstrates that tidal disruption events can generate circumbinary gas rings around supermassive black hole binaries, which may fragment or form gaseous discs, influencing gas supply in galactic nuclei.

Contribution

It introduces a novel mechanism by which tidal disruptions produce circumbinary discs or rings around supermassive black hole binaries, supported by simulations.

Findings

Tidal disruptions can create circumbinary rings around black hole binaries.

These rings can fragment into clumps or evolve into gaseous discs.

The process replenishes gas reservoirs in galactic nuclei.

Abstract

Tidal disruption events, which occur when a star is shredded by the tidal field of a supermassive black hole, provide a means of fueling 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 supermassive black hole 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 supermassive black hole binaries and, more generally, can replenish the reservoir of gas on very small scales in galactic nuclei.