Mapping and characterization of cosmic filaments in galaxy cluster outskirts: Strategies and forecasts for observations from simulations

Upcoming wide-field surveys are well suited to studying the growth of galaxy clusters by tracing galaxy and gas accretion along cosmic filaments. We use hydrodynamic simulations of volumes surrounding 324 clusters from The ThreeHundred project to develop a framework for identifying and characterizing these filamentary structures and associating galaxies with them. We define three-dimensional reference filament networks reaching 5R200 based on the underlying gas distribution and quantify their recovery using mock galaxy samples mimicking observations such as those of the WEAVE Wide-Field Cluster Survey. Since massive galaxies trace filaments, they are best recovered by mass-weighting galaxies or imposing a bright limit (e.g. >L∗) on their selection. We measure the transverse gas density profile of filaments, derive a characteristic filament radius of ≥ 0.7-1 h-1Mpc, and use this to assign galaxies to filaments. For different filament extraction methods, we find that at R > R200, ∼15-20 per cent of galaxies with M∗ > 3 × 109M≥ are in filaments, increasing to 60 per cent for galaxies more massive than the Milky Way. The fraction of galaxies in filaments is independent of cluster mass and dynamical state and is a function of cluster-centric distance, increasing from ∼13 per cent at 5R200 to ∼21 per cent at 1.5R200. As a bridge to the design of observational studies, we measure the purity and completeness of different filament galaxy selection strategies. Encouragingly, the overall three-dimensional filament networks and ∼67 per cent of the galaxies associated with them are recovered from two-dimensional galaxy positions.Fil: Kuchner, Ulrike. The University Of Nottingham. School Of Physics & Astronomy; Reino Unido. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Aragón-Salamanca, Alfonso. The University Of Nottingham. School Of Physics & Astronomy; Reino Unido. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Pearce, Frazer R.. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino Unido. The University Of Nottingham. School Of Physics & Astronomy; Reino UnidoFil: Gray, Meghan E. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino Unido. The University Of Nottingham. School Of Physics & Astronomy; Reino UnidoFil: Rost, Agustín Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mu, Chunliang. Department Of Physics, Fudan University; República de China. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Welker, Charlotte. Mc Master University; CanadáFil: Cui, Weiguang. University of Edinburgh; Reino UnidoFil: Haggar, Roan. The University Of Nottingham. School Of Physics & Astronomy; Reino Unido. Science and Technology Facilities Council of Nottingham. Rutherford Appleton Laboratory; Reino UnidoFil: Laigle, Clotilde. Sorbonne University; FranciaFil: Knebe, Alexander. Universidad Autónoma de Madrid; España. University of Western Australia; AustraliaFil: Kraljic, Katarina. University of Edinburgh; Reino UnidoFil: Sarron, Florian. The University Of Nottingham. School Of Physics & Astronomy; Reino UnidoFil: Yepes, Gustavo. Universidad Autónoma de Madrid; Españ