Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations

Ulrike Kuchner; Alfonso Aragón-Salamanca; Frazer R. Pearce; Meghan E. Gray; Agustín Rost; Chunliang Mu; Charlotte Welker; Weiguang Cui; Roan Haggar; Clotilde Laigle; Alexander Knebe; Katarina Kraljic; Florian Sarron; Gustavo Yepes

doi:10.1093/mnras/staa1083

paper

Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations

arXiv:2004.08408 · doi:10.1093/mnras/staa1083

Abstract

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 \textsc{The ThreeHundred} project to develop a framework for identifying and characterising these filamentary structures, and associating galaxies with them. We define 3-dimensional reference filament networks reaching $5 R_{200}$ 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 $≃ 0.7$ -- $1 h^{- 1} Mpc$ , and use this to assign galaxies to filaments. For different filament extraction methods we find that at $R > R_{200}$ , $\sim 15$ -- $20$ of galaxies with $M_{*} > 3 \times 1 0^{9} M_{⊙}$ are in filaments, increasing to $\sim 60$ 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 $\sim 13$ % at $5 R_{200}$ to $\sim 21$ % at $1.5 R_{200}$ . As a bridge to the design of observational studies, we measure the purity and completeness of different filament galaxy selection strategies. Encouragingly, the overall 3-dimensional filament networks and $\sim 67$ % of the galaxies associated with them are recovered from 2-dimensional galaxy positions.

arXiv comment22 pages, 17 figures, accepted for publication in MNRAS

Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations

Abstract

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