The evolution of baryonic mass function of galaxies to z=3

TL;DR

This paper investigates the evolution of the baryonic mass function of galaxies up to redshift 3, revealing a transition from accretion-dominated to depletion-dominated growth around redshift 1.5, linked to the decline in cosmic star formation.

Contribution

It combines stellar mass functions and gas relations to analyze baryonic mass evolution and the transition in galaxy growth phases over cosmic time.

Findings

Baryonic mass function evolves little for massive galaxies since z~2.2.

The ratio of baryon accretion to star formation decreases from 2 to below 0.5 from z~2.5 to z~0.5.

Transition from accretion to depletion phase occurs at z~1.5.

Abstract

We combine the published stellar mass function (SMF) and gas scaling relations to explore the baryonic (stellar plus cold gas) mass function (BMF) of galaxies to redshift $z=3$. We find evidence that at log$(M_{\rm baryon}/M_{\bigodot})>11.3$, the BMF evolves little since $z\sim 2.2$. With the evolution of BMF and SMF, we investigate the baryon net accretion rate ($\dot{\rho}_{\rm baryon}$) and stellar mass growth rate ($\dot{\rho}_{\rm star}$) for the galaxy population of log($M_{\rm star}/M_{\bigodot}$)>10. The ratio between these two quanties, $\dot{\rho}_{\rm baryon}$/$\dot{\rho}_{\rm star}$, decreases from $\dot{\rho}_{\rm baryon}$/$\dot{\rho}_{\rm star}\sim$2 at $z\sim 2.5$ to $\dot{\rho}_{\rm baryon}$/$\dot{\rho}_{\rm star}<$0.5 at $z\sim 0.5$, suggesting that massive galaxies are transforming from the "accretion dominated" phase to the "depletion dominated" phase from high$-z$ to low$-z$. The transition of these two phases occurs at $z\sim1.5$, which is consistent with the onset redshift of the decline of cosmic star formation rate density. This provides evidence to support the idea that the decline of cosmic star formation rate density since $z\sim1.5$ is mainly resulted from the decline of baryon net accretion rate and star formation quenching in galaxies.