From the Densest Clusters to the Emptiest Voids: No Evidence For Environmental Effects on the Galaxy Size-Mass Relation at Low Redshift

TL;DR

This study analyzes the galaxy size-stellar mass relation at low redshift across various environments and finds no significant environmental influence, supporting the universality of the relation.

Contribution

It provides the first comprehensive analysis showing the galaxy size-mass relation is unaffected by environment at low redshift, across multiple spatial scales.

Findings

Galaxy SMR shows no dependence on environment at fixed stellar mass.

Cluster and void galaxies follow similar SMR trends.

Early-type galaxies have steeper SMR slopes than late types.

Abstract

We present a comprehensive study of the galaxy size-stellar mass relation (SMR) at low redshift (z <= 0.125), using a large spectroscopic sample from the SDSS-DR13 survey. Our goal is to investigate how environment affects galaxy structural properties across multiple spatial scales. Galaxies are classified by specific star formation rate, optical color, and bulge-to-total light ratio, allowing us to disentangle environmental effects from intrinsic galaxy properties. We examine the SMR in three contexts: (1) comparing galaxy sizes in two extreme environments-dense clusters versus cosmic voids; (2) analyzing cluster galaxies across a range of cluster masses; and (3) studying member galaxies located in different cluster regions, from the core to the infall zone. In all three cases, we find no significant dependence of the SMR on environment at fixed stellar mass and galaxy type. Cluster and void galaxies follow consistent SMR trends, and no measurable variation is observed with cluster mass or cluster-centric distance. We also confirm that early-type galaxies exhibit steeper SMR slopes than late types. Notably, this consistent lack of environmental dependence on the SMR persists even when accounting for the differing galaxy number densities in voids, supporting the universality of this SMR scaling relation across diverse environments.