The cosmic web formed through the gravitational amplification of tiny primordial density fluctuations. Its main components—voids, walls, filaments, and nodes—are connected by a continuous flow of matter, from the nearly empty voids to the dense nodes where galaxy clusters reside. However, the role these structures play in shaping the evolution of galaxies and clusters remains an open question.
In this talk, I will present our recent findings on two key aspects: (1) the influence of filaments on the gas fraction of galaxy clusters, and (2) their impact on individual galaxies, particularly in terms of stellar colours and star formation rates (SFR).
Regarding the first point, we find hints that galaxy clusters with higher gas fractions tend to lie closer to the filament spine. We interpret this result as filaments acting like a cage that traps gas expelled by AGN feedback, shortening the gas recycling timescale. As a result, a larger amount of gas remains confined in the central regions of the cluster, where the gas fraction is typically measured.
On the galaxy scale, we investigate how galaxy colours and SFRs vary as a function of distance from the spine of nearest filament (Dfila). We find a clear trend: galaxies become redder and less star-forming as they approach the filament spine. This trend cannot be attributed to morphological transformations, suggesting that filaments influence star formation without significantly altering galaxy structure. A possible explanation is provided by the Cosmic Web Detachment model, which suggests that the presence of a filament can suppress the accretion of gas by the galaxy. This leads to a decline in SFR around Dfila = 5 Mpc and a subsequent reddening of the stellar population at about Dfila = 2.5 Mpc.