Gas accretion in disk galaxies

TL;DR

This paper reviews how gas accretion from various processes sustains galaxy evolution, star formation, and active galactic nuclei activity, emphasizing recent progress in observations and simulations across cosmic time.

Contribution

It synthesizes current understanding of gas accretion mechanisms, their dynamical effects, and the progress in observational and simulation studies from moderate to high redshifts.

Findings

Gas accretion drives star formation and galaxy dynamics.

Simulations and observations confirm the importance of cosmic filaments.

Progress enables interpretation of star formation history across redshifts.

Abstract

Gas accretion is necessary to maintain star formation, spiral and bar structure, and secular evolution in galaxies. This can occur through tidal interaction, or mass accretion from cosmic filaments. Different processes will be reviewed to drive gas towards galaxy centers and trigger starbursts and AGN. The efficiency of these dynamical processes can be estimated through simulations and checked by observations at different redshift, across the Hubble time. Large progress has been made on galaxies at moderate and high redshifts, allowing to interpret the star formation history and star formation efficiency as a function of gas content, dynamical state and galaxy evolution.