The effect of differential accretion on the Gravitational Wave Background and the present day MBH Binary population

Understand

Massive black hole binaries (MBHBs) form as a consequence of galaxy mergers.

• However, it is still unclear whether they typically merge within a Hubble time, and how accretion may affect their evolution.
• These questions will be addressed by pulsar timing arrays (PTAs), which aim to detect the GW background (GWB) emitted by MBHBs during the last Myrs of inspiral.
• Here we investigate the influence of differential accretion on MBHB merger rates, chirp masses and the resulting GWB spectrum.