Local and large-scale effects on the astrophysics of void-galaxies

TL;DR

This study investigates how large-scale cosmic voids influence galaxy properties, revealing that environment impacts galaxy evolution, especially in low-mass haloes and different void types, indicating second-order environmental effects.

Contribution

It provides a detailed analysis of galaxy properties in different void environments and their dependence on large-scale structure, highlighting the environmental influence beyond local density effects.

Findings

Galaxies in voids are bluer and have higher star formation rates in low-mass haloes.

Galaxy properties vary between S-type and R-type voids, with R-type hosting more active galaxies.

Environmental effects on galaxy evolution extend beyond local density, influenced by large-scale void characteristics.

Abstract

Galaxies in cosmic voids have been reported with properties related to a delayed evolution with respect to the Universe in general. These characteristics reflect the interaction of galaxies with the environment. However, it is not clear the degree of influence of the large-scale structure on the properties of void galaxies or, if these are only influenced by the low local density around them typical of these regions. In this article we identified cosmic voids in the SDSS-DR16 and studied various properties of galaxies, such as g-r colour, star formation rate, and concentration. To characterise the local environment, we have identified groups of galaxies and studied their properties as a function of their dark matter and stellar masses, analysing separately those found in voids and in the general sample. Our results show that galaxies that inhabit haloes of a given mass (below \sim 10^13.5 M_\dot ), are bluer, have a higher star formation rate and are less concentrated when the host halo is inside voids compared to other regions. For larger halo masses, the trend disappears. We also analyse whether the properties of galaxies are sensitive to the type of voids that inhabit. This is done by separating voids embedded in overdense regions (S-type) from those that asymptotically converge to the average density of the universe (R-type). We found that galaxies in R-type voids are bluer, with higher SFR and less concentration than in S-type voids. Our results indicate some degree of correlation of galaxy properties with the large-scale environment provided by voids, suggesting possible second-order mechanisms in galaxy evolution.