Monday

Filaments are ubiquitous in the Universe. ΛCDM-based cosmological simulations indicate that galaxy clusters sit at the nodes of these filaments. In order to trace the impact of structure growth via filaments on the galaxy population, we must therefore consider galaxies in groups and cosmic filaments well beyond the cluster’s virial radius.

At low redshifts, observations deliver high data quality, but the large area, combined with their lower contrast, means that these regions are largely unexplored. In response to these challenges, we have designed the WEAVE Wide-Field Cluster Survey (WWFCS) to map the filaments around local clusters spectroscopically out to ~5Rvir: We selected 20 well-studied clusters at z~0.05, which will be observed with the WEAVE instrument at the WHT. Given the high spatial sampling, and aided by dedicated auxiliary data, we predict to observe ~5000 galaxies over a broad range of masses (10^9 Mʘ M* 10^11.5 Mʘ) per cluster structure.

The survey is expected to have its first light in less than a year. To develop and test structure-finding methods, we are using the DisPerSE algorithm on simulations from the Three Hundred project. These are re-simulations of the 324 most massive galaxy clusters and their surrounding environment from the MultiDark 1Gpc/h simulation. With these full-physics simulations, we are able to compare filament networks based on Dark Matter particles, gas and galaxies. Crucially, we can model the relative importance of the various physical processes experienced in each environment in transforming galaxies.