The Three Hundred Project: Backsplash galaxies in simulations of clusters

Abstract

In the outer regions of a galaxy cluster, galaxies may be either falling into the cluster for the first time, or have already passed through the cluster centre at some point in their past. To investigate these two distinct populations, we utilise TheThreeHundred project, a suite of 324 hydrodynamical resimulations of galaxy clusters. In particular, we study the 'backsplash population' of galaxies; those that have passed within $R_{200}$ of the cluster centre at some time in their history, but are now outside of this radius. We find that, on average, over half of all galaxies between $R_{200}$ and $2R_{200}$ from their host at $z=0$ are backsplash galaxies, but that this fraction is dependent on the dynamical state of a cluster, as dynamically relaxed clusters have a greater backsplash fraction. We also find that this population is mostly developed at recent times ($z\le 0.4$), and is dependent on the recent history of a cluster. Finally, we show that the dynamical state of a given cluster, and thus the fraction of backsplash galaxies in its outskirts, can be predicted based on observational properties of the cluster.

13 pages, 12 figures, accepted for publication in MNRAS

References in corpus (8)

• Rotation-Dependent Catastrophic Disruption of Gravitational Aggregates
• Dark matter and cosmic structure
• LoCuSS: The slow quenching of star formation in cluster galaxies and the need for pre-processing
• Splashback in accreting dark matter halos
• A dynamical model of the local cosmic expansion
• The Evolution of the Field and Cluster Morphology-Density Relation for Mass-Selected Samples of Galaxies
• The Three Hundred Project: Ram pressure and gas content of haloes and subhaloes in the phase-space plane
• Rhapsody. II. Subhalo Properties and the Impact of Tidal Stripping From a Statistical Sample of Cluster-Size Halos

Cited by in corpus (5)

• Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations
• The Three Hundred project: shapes and radial alignment of satellite, infalling, and backsplash galaxies
• The Three Hundred Project: the stellar and gas profiles
• Dwarfs in the Milky Way halo outer rim: first in-fall or backsplash satellites?
• Protoclusters at z=5.7: A view from the MultiDark galaxies