Disentangling the role of environmental processes in galaxy clusters

TL;DR

This study introduces a novel statistical approach to disentangle environmental effects on star-forming galaxies in clusters, revealing how different luminosity groups are affected by processes like starvation and harassment across various cluster regions.

Contribution

The paper presents a new method analyzing NUV-r' distributions to identify environmental processes impacting galaxies, considering their luminosity and location within clusters.

Findings

High-luminosity galaxies show no recent environmental impact.

Intermediate-luminosity galaxies affected by starvation and harassment.

Low-luminosity galaxies experience stronger environmental effects.

Abstract

In this work we present the results of a novel approach devoted to disentangle the role of the environmental processes affecting galaxies in clusters. This is based on the analysis of the NUV-r' distributions of a large sample of star-forming galaxies in clusters spanning more than four absolute magnitudes. The galaxies inhabit three distinct environmental regions: virial regions, cluster infall regions and field environment. We have applied rigorous statistical tests in order to analyze both, the complete NUV-r' distributions and their averages for three different bins of r'-band galaxy luminosity down to M_r' ~ -18, throughout the three environmental regions considered. We have identified the environmental processes that significantly affect the star-forming galaxies in a given luminosity bin by using criteria based on the characteristics of these processes: their typical time-scales, the regions where they operate and the galaxy luminosity range for which their effects are more intense. We have found that the high-luminosity (M_r'<=-20) star-forming galaxies do not show significant signs in their star formation activity neither of being affected by the environment in the last ~10^8 yr nor of a sudden quenching in the last 1.5 Gyr. The intermediate-luminosity (-20<M_r'<=-19) star-forming galaxies appear to be affected by starvation in the virial regions and by the harassment both, in the virial and infall regions. Low-luminosity (-19<M_r'<=-18.2) star-forming galaxies seem to be affected by the same environmental processes as intermediate-luminosity star-forming galaxies in a stronger way, as it would be expected for their lower luminosities.