The Stellar Mass Fundamental Plane and Compact Quiescent Galaxies at z < 0.6

TL;DR

This study investigates the evolution of the stellar mass fundamental plane for quiescent galaxies at redshifts below 0.6, finding that the relation's orientation remains consistent over time while sizes decrease slightly, and compact galaxies are part of the normal population.

Contribution

It provides the first detailed analysis of the fundamental plane evolution at low redshift, showing size evolution and confirming compact galaxies are part of the normal quiescent galaxy distribution.

Findings

Velocity dispersion distribution is similar at different redshifts.

Galaxies at z<0.6 are slightly smaller than local counterparts.

Compact galaxies follow the same fundamental plane relation as larger ones.

Abstract

We examine the evolution of the relation between stellar mass surface density, velocity dispersion and half-light radius$-$the stellar mass fundamental plane$-$for quiescent galaxies at $z<0.6$. We measure the local relation from galaxies in the Sloan Digital Sky Survey and the intermediate redshift relation from $\sim500$ quiescent galaxies with stellar masses $10 \lesssim \mathrm{log}(M_\ast/M_\odot) \lesssim 11.5$. Nearly half of the quiescent galaxies in our intermediate redshift sample are compact. After accounting for important selection and systematic effects, the velocity dispersion distribution of galaxies at intermediate redshifts is similar to galaxies in the local universe. Galaxies at $z<0.6$ appear to be smaller ($\lesssim0.1$ dex) than galaxies in the local sample. The orientation of the stellar mass fundamental plane is independent of redshift for massive quiescent galaxies at $z<0.6$ and the zero-point evolves by $\sim 0.04$ dex. Compact quiescent galaxies fall on the same relation as the extended objects. We confirm that compact quiescent galaxies are the tail of the size and mass distribution of the normal quiescent galaxy population.