On the intermediate-redshift central stellar mass-halo mass relation, and implications for the evolution of the most massive galaxies since z~1

TL;DR

This study shows that the relation between stellar mass and halo mass for massive galaxies is steeper than previously thought up to redshift 1, indicating a strong link between galaxy and halo growth in recent cosmic history.

Contribution

The paper provides new evidence for a steeper high-mass end slope of the stellar mass-halo mass relation up to z~1, and constrains the scatter in stellar mass at fixed halo mass for massive galaxies.

Findings

High-mass end slope .35-0.70, steeper than earlier estimates.

Consistent small scatter (<0.15 dex) in stellar mass at fixed halo mass for Mstar>3e11 Msun.

Supports a close galaxy-halo connection at z<0.8.

Abstract

The stellar mass-halo mass relation is a key constraint in all semi-analytic, numerical, and semi-empirical models of galaxy formation and evolution. However, its exact shape and redshift dependence remain debated. Several recent works support a relation in the local Universe steeper than previously thought. Based on the comparisons with a variety of data on massive central galaxies, we show that this steepening holds up to z~1, for stellar masses Mstar>2e11 Msun. Specifically, we find significant evidence for a high-mass end slope of \beta>0.35-0.70, instead of the usual \beta~0.20-0.30 reported by a number of previous results. When including the independent constraints from the recent BOSS clustering measurements, the data, independent of any systematic errors in stellar masses, tend to favor a model with a very small scatter (< 0.15 dex) in stellar mass at fixed halo mass, in the redshift range z < 0.8 and for Mstar>3e11 Msun, suggesting a close connection between massive galaxies and host halos even at relatively recent epochs. We discuss the implications of our results with respect to the evolution of the most massive galaxies since z~1.