Capture of stars into gaseous discs around massive black holes: Alignment, circularization and growth

Understand

The majority of massive black holes (MBHs) likely hosted gas discs during their lifetimes.

• These could either be long-lived active galactic nuclei (AGN) discs, or shorter-lived discs formed following singular gas infall events, as was likely the case in our own Galactic Center.
• Stars and compact objects in such environments are therefore expected to interact with the gaseous disc as they go through it, and potentially become aligned and fully embedded within it.
• The interactions of embedded stars with the gas could give rise to a plethora of physical processes affecting the stars, including growth through accretion of gas, migration in the disc, stellar captures, and mergers with other stars.