Accretion of small satellites and gas inflows in a disc galaxy

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% 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.

VV 655 and NGC 4418: Implications of an interaction for the evolution of a LIRG

“…The third scenario to consider is that the perigalacticon passage of VV 655, likely on a prograde orbit, perturbed the pre-existing ISM in NGC 4418 and led to its central concentration. A variety of models show that a satellite with an SMC-like mass, such as VV 655, can produce tidal torques that result in a significant inward migration of the initial gas disk (Pettitt et al 2016;Ramón-Fox & Aceves 2019). Indeed, the possibility of an interaction-induced inflow of molecular gas in the nucleus of NGC 4418 was raised by Kawara et al (1990) and González-Alfonso et al (2012).…”