Galaxy mass-size segregation in the cosmic web from the CAVITY parent sample

TL;DR

This study investigates how large-scale cosmic environments like voids, filaments, and clusters affect the galaxy mass-size relation, revealing environment-dependent differences in galaxy sizes and growth patterns across various galaxy types.

Contribution

It provides the first detailed analysis of the impact of large-scale environments on the galaxy mass-size relation using extensive SDSS and CAVITY data, highlighting environment-specific growth trends.

Findings

Early-type void galaxies are 10-20% smaller than in denser regions.

Massive early-type void galaxies have a shallower mass-size relation slope.

Late-type cluster galaxies are smaller and more concentrated than in less dense environments.

Abstract

The mass-size relation is a fundamental galaxy scaling law closely tied to galaxy formation and evolution. Using added-value products of the Calar Alto Void Integral-field Treasury surveY (CAVITY) and SDSS DR16 images, we examine the effect of large-scale environments on the stellar mass-size relation. We analyse the Petrosian R50 and R90 radii of approximately 140000 galaxies in voids, filaments, and clusters, with a mass range of $10^{8.5} - 10^{11} M_{\odot}$. We explore the relation in terms of galaxy morphology and star formation history, parametrised by T50, T70, and T90. We find that early-type void galaxies are, on average, 10-20% smaller than their counterparts in denser environments, regardless of their mass assembly history. Moreover, the mass-size relation for massive early-type void galaxies has a shallower slope compared to those in denser regions. In contrast, early-type galaxies in filaments, and clusters show a more uniform mass-size relation. Late-type cluster galaxies with stellar masses $log(M_{\star} / M_{\odot}) = 9 - 10.5$ are smaller and more concentrated than their counterparts in lower-density environments, such as filaments, and voids. We conclude that large-scale environments influence the mass-size relation. Early-type galaxies appear to grow most of their mass during the initial formation phase. Subsequent size growth in voids is less significant, likely due to slower evolution, reduced minor merger activity, fewer accretion events, or a combination. The flatter slope for massive void galaxies indicates a lower rate of minor accretion, a trend also observed in late-type void galaxies with $\approx 10^{10.5} M_{\odot}$, where minor mergers contribute to size growth. Conversely, late-type quenched cluster galaxies are smaller due to environmental interactions, with early infallers being most affected.