Cookie-cutter halos: the remarkable constancy of the stellar mass function of satellite galaxies at 0.2<z<1.2

TL;DR

This study reveals that the stellar mass function of satellite galaxies remains remarkably consistent across redshifts 0.2 to 1.2 and varies primarily with the mass of the central galaxy, indicating a universal pattern in galaxy group evolution.

Contribution

It demonstrates the near-universality of satellite galaxy mass functions across redshifts and links satellite growth to central galaxy mass, using statistical background subtraction techniques.

Findings

Satellite stellar mass functions increase with central galaxy mass.

Minimal redshift dependence of satellite mass functions at fixed central mass.

Quiescent satellite fraction increases with central galaxy mass.

Abstract

We present an observational study of the stellar mass function of satellite galaxies around central galaxies at 0.2<z<1.2. Using statistical background subtraction of contaminating sources we derive satellite stellar mass distributions in four bins of central galaxy mass in three redshift ranges. Our results show that the stellar mass function of satellite galaxies increases with central galaxy mass, and that the distribution of satellite masses at fixed central mass is at most weakly dependent on redshift. We conclude that the average mass distribution of galaxies in groups is remarkably universal even out to z=1.2 and that it can be uniquely characterized by the group central galaxy mass. This further suggests that as central galaxies grow in stellar mass, they do so in tandem with the mass growth of their satellites. Finally, we classify all galaxies as either star forming or quiescent, and derive the mass functions of each subpopulation separately. We find that the mass distribution of both star forming and quiescent satellites show minimal redshift dependence at fixed central mass. However, while the fraction of quiescent satellite galaxies increases rapidly with increasing central galaxy mass, that of star forming satellites decreases.