Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas

Understand

Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies.

• It is normally assumed that, following the merger of two massive galaxies, a SMBH binary will form, shrink due to stellar or gas dynamical processes and ultimately coalesce by emitting a burst of gravitational waves.
• However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas due to the difficulty of modeling a wide range of spatial scales.
• Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years following the collision between two spiral galaxies.