Relating galaxies across different redshift to study galaxy evolution

TL;DR

This paper introduces a statistical framework linking galaxies across different redshifts via the halo-galaxy connection, enabling the study of galaxy evolution and mass assembly histories up to redshift 3 using simulations and observational data.

Contribution

It presents a novel method to relate galaxies at different redshifts and accurately infer their stellar mass evolution, validated with hydrodynamic simulations and applied to real data.

Findings

Galaxies in low-mass halos grow faster than those in massive clusters since z~1.8.

Star-forming galaxies grow 2-4 times faster than quiescent ones since z~1.8.

Simulations over-predict progenitor stellar mass at z>1, especially for low-mass galaxies.

Abstract

We propose a general framework leveraging the halo-galaxy connection to link galaxies observed at different redshift in a statistical way, and use the link to infer the redshift evolution of the galaxy population. Our tests based on hydrodynamic simulations show that our method can accurately recover the stellar mass assembly histories up to $z\sim 3$ for present star-forming and quiescent galaxies down to $10^{10}h^{-1}M_{\odot}$. Applying the method to observational data shows that the stellar mass evolution of the main progenitors of galaxies depends strongly on the properties of descendants, such as stellar mass, halo mass, and star formation states. Galaxies hosted by low-mass groups/halos at the present time have since $z\sim 1.8$ grown their stellar mass $\sim 2.5$ times as fast as those hosted by massive clusters. This dependence on host halo mass becomes much weaker for descendant galaxies with similar star formation states. Star-forming galaxies grow about 2-4 times faster than their quiescent counterparts since $z\sim 1.8$. Both TNG and EAGLE simulations over-predict the progenitor stellar mass at $z>1$, particularly for low-mass descendants.