Evolution of the Stellar-to-Dark Matter Relation: Separating Star-Forming and Passive Galaxies from z=1 to 0

TL;DR

This study analyzes how the relationship between stellar mass and dark matter halos evolves from redshift 1 to 0, revealing different growth patterns for star-forming and quiescent galaxies and their quenching mechanisms.

Contribution

It provides new insights into the evolution of the stellar-to-halo mass relation for different galaxy types and the changing efficiency of quenching processes over cosmic time.

Findings

Star-forming galaxies grow proportionally with dark matter halos at high masses.

Quiescent galaxies are outpaced by dark matter growth at high masses.

Most low-mass quiescent galaxies have recently been quenched.

Abstract

We use measurements of the stellar mass function, galaxy clustering, and galaxy-galaxy lensing within the COSMOS survey to constrain the stellar-to-halo mass relation (SHMR) of star forming and quiescent galaxies over the redshift range z=[0.2,1.0]. For massive galaxies, M*>~10^10.6 Msol, our results indicate that star-forming galaxies grow proportionately as fast as their dark matter halos while quiescent galaxies are outpaced by dark matter growth. At lower masses, there is minimal difference in the SHMRs, implying that the majority low-mass quiescent galaxies have only recently been quenched of their star formation. Our analysis also affords a breakdown of all COSMOS galaxies into the relative numbers of central and satellite galaxies for both populations. At z=1, satellite galaxies dominate the red sequence below the knee in the stellar mass function. But the number of quiescent satellites exhibits minimal redshift evolution; all evolution in the red sequence is due to low-mass central galaxies being quenched of their star formation. At M*~10^10 Msol, the fraction of central galaxies on the red sequence increases by a factor of ten over our redshift baseline, while the fraction of quenched satellite galaxies at that mass is constant with redshift. We define a "migration rate" to the red sequence as the time derivative of the passive galaxy abundances. We find that the migration rate of central galaxies to the red sequence increases by nearly an order of magnitude from z=1 to z=0. These results imply that the efficiency of quenching star formation for centrals is increasing with cosmic time, while the mechanisms that quench the star formation of satellite galaxies in groups and clusters is losing efficiency.