Non-steady-state long-term evolution of supermassive black hole binaries surrounded by accretion discs

Understand

Supermassive black holes (SMBHs) pair and form bound binaries after their host galaxies merge.

• In a gas-rich merger, accretion discs are expected to form around the binary and its components.
• These discs control the binary orbital evolution until the system is compact enough for gravitational waves to drive the SMBHs to coalescence.
• In this work, we implemented a time-dependent 1D model to follow the long-term evolution of the coupled binary + discs system, from a separation of 10^5 down to 20 Schwarzschild radii.