The evolution of substructure - III. The outskirts of clusters

By Stuart P. D. Gill, A. Knebe, B. Gibson. 2004

198 citations recorded by the source corpus.

We present an investigation of satellite galaxies in the outskirts of galaxy clusters taken from a series of high-resolution N-body simulations. We focus on the so-called backsplash population, i.e. satellite galaxies that once were inside the virial radius of the host but now reside beyond it. We find that this population is significant in number and needs to be appreciated when interpreting the various galaxy morphology environmental relationships and decoupling the degeneracy between nature and nurture. Specifically, we find that approximately half of the galaxies with current cluster-centric distance in the interval 1-2 virial radii of the host are backsplash galaxies that once penetrated deep into the cluster potential, with 90 per cent of these entering to within 50 per cent of the virial radius. These galaxies have undergone significant tidal disruption, losing on average 40 per cent of their mass. This results in a mass function for the backsplash population different from those galaxies infalling for the first time. We further show that these two populations are kinematically distinct and should be observable within existent spectroscopic surveys.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/3d8b0397c693ca8c4b232e5bb7095fe3e32db59f

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Citations in the corpus

ELVIS: Exploring the Local Volume in Simulations (2013, background): “We refer to previously-interacted objects of this kind as “backsplash” haloes (e.g., Gill et al. 2005 and references therein).”
Gaia DR2 proper motions of dwarf galaxies within 420 kpc (2018, background): “Such satellites can be considered alongside the backsplash population of satellites that exist beyond the virial radius at z=0 in simulations, but have been within the virial radius at earlier times (Balogh et al. 2000; Gill et al. 2005; Teyssier et al. 2012; Simpson et al. 2018).”
THE SPLASHBACK RADIUS AS A PHYSICAL HALO BOUNDARY AND THE GROWTH OF HALO MASS (2015, background): “…previously in the context of “backsplash satellites” which were found in substantial numbers beyond the halo radii in the standard definitions (Balogh et al. 2000; Mamon et al. 2004; Gill et al. 2005, see also Wetzel et al. 2014 for in depth analysis of this issue and more recent references).”
Star formation and AGN activity in SDSS cluster galaxies (2009, background): “It has been suggested that an appreciable fraction of galaxies observed at∼ 1 − 3R200 previously passed through the cluster (e.g. Balogh et al. 2000; Gill et al. 2005; Ludlow et al. 2009).”
Substructures in hydrodynamical cluster simulations (2008, background): “Note that a substantial fraction of these subhalos detected at r > Rvir may have already crossed the cluster virial region in earlier passages and constitute the so-called “backsplash population” (see Gill et al. 2005; Ludlow et al. 2008).”
LoCuSS: THE SLOW QUENCHING OF STAR FORMATION IN CLUSTER GALAXIES AND THE NEED FOR PRE-PROCESSING (2015, background): “Biviano & Katgert (2004) showed that if early-type galaxies are assumed to have isotropic orbits within clusters, as supported by their Gaussian velocity distributions, the kinematic properties of late-type spirals are inconsistent with being isotropic at the >99% level.”
THE UNORTHODOX ORBITS OF SUBSTRUCTURE HALOS (2008, result): “…discrepancy between the simulation results and the naive expectation of the SSIM was pointed out by Balogh, Navarro & Morris (2000), and confirmed by subsequent studies (Mamon et al 2004, Gill et al 2005, Diemand et al 2007) but its physical origin has not yet been conclusively pinned down.”
THE SPACE MOTION OF LEO I: THE MASS OF THE MILKY WAY'S DARK MATTER HALO (2012, background): “…ΛCDM simulations find, that many satellites once well within a host’s virial radius will spend significant time at larger radii (Mamon et al. 2004; Gill et al. 2005; Wang et al. 2009), a natural consequence of the highly eccentric nature of subhalo orbits (the median apocenter to pericenter…”
Formation and Evolution of Galaxy Dark Matter Halos and Their Substructure (2007, background): “To summarize, we confirm the (Balogh et al. 2000; Moore et al. 2004; Gill et al. 2005) result that many subhalos end up in the field (according to common definitions) and we illustrate that this leads to a clear environment dependence of halo assembly histories like those found in (Gao et al. 2005;…”
A Fitting Formula for the Merger Timescale of Galaxies in Hierarchical Clustering (2007, background): “…et al. 2003; Khochfar & Ostriker 2007; Baugh 2006, for an excellent review) and in understanding the merger rates of galaxies in the cosmological context (e.g. Ostriker & Turner 1979; Lin et al. 2004; Gill et al. 2005; Maller et al. 2006; Conroy et al. 2007; White et al. 2007; Zheng et al. 2007).”
Galaxy evolution in groups and clusters: satellite star formation histories and quenching time-scales in a hierarchical Universe (2012, background): “The latter also naturally incorporates satellites that temporarily orbit beyond their host halo’s virial radius, Rvir, which we call ‘ejected satellites’, and then fall in again (Gill et al. 2005; Ludlow et al. 2009; Wang et al. 2009).”