Hierarchical structure of the cosmic web and galaxy properties

Abstract

ABSTRACT Voids possess a very complex internal structure and dynamics. Using N-body simulations, we study the hierarchical nature of sub-structures present in the cosmic web (CW). We use the $\tt {SpineWeb}$ method which provides a complete characterization of the CW into its primary constituents: voids, walls, filaments, and nodes. We aim to characterize the inner compositions of voids by detecting their internal CW structure and explore the impact of this on the properties of void galaxies. Using a semi-analytical galaxy evolution model, we explore the impact of the CW on several galaxies’ properties. We find the number fraction of haloes living in various CW components to be a function of their mass, with the majority of the haloes of mass below 1012 M⊙ h−1, residing in voids and haloes of higher masses distributed mostly in walls. Similarly, in the stellar-to-halo mass relationship, we observe an environmental dependence for haloes of masses below 1012 M⊙ h−1, showing an increased stellar mass fraction for the galaxies identified in the densest environments. The spin is lower for galaxies in the densest environments for the mass range of 1010−1012 M⊙ h−1. Finally, we found a strong trend of higher metallicity fractions for filaments and node galaxies, with respect to the full sample, in the range of $M_*\stackrel{\lt }{{}_\sim }10^{10}$ M⊙ h−1. Our results show that cosmic voids possess an intricate internal network of substructures. This, in turn, makes them a complex environment for galaxy formation, impacting in an unique way the properties and evolution of the chosen few galaxies that form inside them.