Cosmic Web and Star Formation Activity in Galaxies at z~1

TL;DR

This study examines how the cosmic web's filamentary structures influence star formation in galaxies at z~1, finding that while key galaxy properties are environment-independent, the fraction of star-forming galaxies is higher in filaments.

Contribution

It introduces a quantitative analysis of the cosmic web's impact on galaxy star formation at z~1 using the MMF algorithm, highlighting the role of filaments in galaxy evolution.

Findings

Star formation rates are environment-independent.

Fraction of Hα emitters is higher in filaments.

Filaments are key environments in galaxy evolution.

Abstract

We investigate the role of the delineated cosmic web/filaments on the star formation activity by exploring a sample of 425 narrow-band selected H{\alpha} emitters, as well as 2846 color-color selected underlying star-forming galaxies for a large scale structure (LSS) at z=0.84 in the COSMOS field from the HiZELS survey. Using the scale-independent Multi-scale Morphology Filter (MMF) algorithm, we are able to quantitatively describe the density field and disentangle it into its major components: fields, filaments and clusters. We show that the observed median star formation rate (SFR), stellar mass, specific star formation rate (sSFR), the mean SFR-Mass relation and its scatter for both H{\alpha} emitters and underlying star-forming galaxies do not strongly depend on different classes of environment, in agreement with previous studies. However, the fraction of H{\alpha} emitters varies with environment and is enhanced in filamentary structures at z~1. We propose mild galaxy-galaxy interactions as the possible physical agent for the elevation of the fraction of H{\alpha} star-forming galaxies in filaments. Our results show that filaments are the likely physical environments which are often classed as the "intermediate" densities, and that the cosmic web likely plays a major role in galaxy formation and evolution which has so far been poorly investigated.