The role of gas infall in the evolution of disc galaxies

TL;DR

This paper investigates how gas infall influences the evolution of spiral galaxy discs, comparing different infall models and simulations to better understand their role in galaxy formation.

Contribution

It introduces infall rates for chemical evolution models, compares them with existing schemes, and contrasts these with cosmological simulations to improve galaxy formation understanding.

Findings

Systematic comparison of infall models with simulations.

Identification of degeneracies in infall rate prescriptions.

Enhanced understanding of gas accretion's role in galaxy evolution.

Abstract

Spiral galaxies are thought to acquire their gas through a protracted infall phase resulting in the inside-out growth of their associated discs. For field spirals, this infall occurs in the lower density environments of the cosmic web. The overall infall rate, as well as the galactocentric radius at which this infall is incorporated into the star-forming disc, plays a pivotal role in shaping the characteristics observed today. Indeed, characterising the functional form of this spatio-temporal infall in-situ is exceedingly difficult, and one is forced to constrain these forms using the present day state of galaxies with model or simulation predictions. We present the infall rates used as input to a grid of chemical evolution models spanning the mass spectrum of discs observed today. We provide a systematic comparison with alternate analytical infall schemes in the literature, including a first comparison with cosmological simulations. Identifying the degeneracies associated with the adopted infall rate prescriptions in galaxy models is an important step in the development of a consistent picture of disc galaxy formation and evolution.