A physical model for the 0 < z < 8 redshift evolution of the galaxy UV luminosity and stellar mass functions

TL;DR

This paper introduces a physical model linking galaxy UV luminosity and stellar mass evolution from redshift 0 to 8 to dark matter halo assembly and gas infall, successfully fitting observed functions without requiring evolving star formation efficiency.

Contribution

The model provides a unified framework for galaxy evolution driven by dark matter halo growth, calibrated at z=4, and predicts the evolution of galaxy properties across cosmic time.

Findings

Model fits the z=4 luminosity and stellar mass functions.

Accurately predicts evolution of galaxy functions from z=0 to 8.

Highlights dark matter halo build-up as primary driver of galaxy evolution.

Abstract

We present a model to understand the redshift evolution of the UV luminosity and stellar mass functions of Lyman Break Galaxies. Our approach is based on the assumption that the luminosity and stellar mass of a galaxy is related to its dark matter halo assembly and gas infall rate. Specifically, galaxies experience a burst of star formation at the halo assembly time, followed by a constant star formation rate, representing a secular star formation activity sustained by steady gas accretion. Star formation from steady gas accretion is the dominant contribution to the galaxy UV luminosity at all redshifts. The model is calibrated by constructing a galaxy luminosity versus halo mass relation at $z=4$ via abundance matching. After this luminosity calibration, the model naturally fits the $z=4$ stellar mass function, and correctly predicts the evolution of both luminosity and stellar mass functions from $z=0$ to $z=8$. While the details of star formation efficiency and feedback are hidden within our calibrated luminosity versus halo mass relation, our study highlights that the primary driver of galaxy evolution across cosmic time is the build-up of dark matter halos, without the need to invoke a redshift dependent efficiency in converting gas into stars.