Accretion of small satellites and gas inflows in a disc galaxy

Abstract

ABSTRACT Galaxy interactions can have an important effect in a galaxy’s evolution. Cosmological models predict a large number of small satellites around galaxies. It is important to study the effect that these small satellites can have on the host. The present work explores the effect of small N-body spherical satellites with total mass ratios in the range ≈ 1:1000-1:100 in inducing gas flows to the central regions of a disc galaxy with late-type morphology resembling the Milky Way. Two model galaxies are considered: barred and non-barred models; the latter one is motivated in order to isolate and understand better the effects of the satellite. Several circular and non-circular orbits are explored, considering both prograde and retrogade orientations. We show that satellites with such small mass ratios can still produce observable distortions in the gas and stellar components of the galaxy. In terms of gas flows, the prograde circular orbits are more favourable for producing gas flows, where in some cases up to $60{{\ \rm per\ cent}}$ of the gas of the galaxy is driven to the central region. We find, hence, that small satellites can induce significant gas flows to the central regions of a disc galaxy, which is relevant in the context of fuelling active galactic nuclei.