  We investigate the fraction of quenched satellite galaxies in host galaxy
groups and clusters using TNG300 in the IllustrisTNG cosmological
magnetohydrodynamical simulations. Simulations show that most satellites are
quenched after they fall into their final hosts: post-processing is a more
dominant mechanism of galaxy quenching than pre-processing. We find the
fraction of quenched satellites at $z=0$ increases with host mass, which
implies that more massive hosts have higher quenching efficiency because more
massive hosts have more massive groups infalling. Furthermore, we find that
hosts that have many early-infall satellites show a higher fraction of quenched
satellites at $z=0$ than those having many late-infall satellites, which
results in a scatter of the quenched fraction of satellites in a given mass
range of hosts at $z=0$. Our results highlight the significance of the mass of
hosts and the different infall times of satellites in understanding galaxy
quenching.
