Shape and connectivity of groups and clusters: Impact of dynamical state and accretion history

Abstract

Matter distribution around clusters is highly anisotropic from their being the nodes of the cosmic web. Clusters' shape and the number of filaments they are connected to, i.e., their connectivity, should reflect their level of anisotropic matter distribution and must be, in principle, related to their physical properties. We investigate the influence of the dynamical state and the formation history on both the morphology and local connectivity of about 2400 groups and clusters of galaxies from the large hydrodynamical simulation IllustrisTNG at z=0. We find that the mass of groups and clusters mainly influences the geometry of the matter distribution: massive halos are significantly more elliptical, and more connected to the cosmic web than low-mass ones. Beyond the mass-driven effect, ellipticity and connectivity are correlated and are imprints of the growth rate of groups and clusters. Both anisotropy measures appear to trace different dynamical states, such that unrelaxed groups and clusters are more elliptical and more connected than relaxed ones. This relation between matter anisotropies and dynamical state is the sign of different accretion histories. Relaxed groups and clusters are mostly formed long time ago, and slowly accreting matter at the present time. They are rather spherical and weakly connected to their environment, mostly because they had enough time to relax and, hence, lost the connection with their preferential directions of accretion and merging. In contrast, late-formed unrelaxed objects are highly anisotropic with large connectivities and ellipticities. These groups and clusters are in formation phase and must be strongly affected by the infalling of materials from filaments.

arXiv commentAccepted to A&A, 13 pages, 11 figures, comments are welcome

References in corpus (68)

• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Observational evidence for self-interacting cold dark matter
• Concentrations of Dark Halos from their Assembly Histories
• MultiDark simulations: the story of dark matter halo concentrations and density profiles
• The statistics of LCDM Halo Concentrations
• The merger rate of galaxies in the Illustris Simulation: a comparison with observations and semi-empirical models
• The Structure of Dark Matter Haloes in Hierarchical Clustering Models
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• Cosmological Simulations with Self-Interacting Dark Matter II: Halo Shapes vs. Observations
• Planck 2015 results. XXIV. Cosmology from Sunyaev-Zeldovich cluster counts
• Evolution of the cosmic web
• Halo Properties in Cosmological Simulations of Self-Interacting Cold Dark Matter
• Tracing the cosmic web
• The redMaPPer Galaxy Cluster Catalog From DES Science Verification Data
• The splashback radius as a physical halo boundary and the growth of halo mass
• Dark matter distribution in the Coma cluster from galaxy kinematics: breaking the mass-anisotropy degeneracy
• The Universal Mass Accretion History of CDM Haloes
• Weakly Self-Interacting Dark Matter and the Structure of Dark Halos
• Multiscale Phenomenology of the Cosmic Web
• Halo and Subhalo Demographics with Planck Cosmological Parameters: Bolshoi-Planck and MultiDark-Planck Simulations
• The diffuse radio emission from the Coma cluster at 2.675 GHz and 4.85 GHz
• The alignment and shape of dark matter, stellar, and hot gas distributions in the EAGLE and cosmo-OWLS simulations
• The dynamical state of the Coma cluster with XMM-Newton
• Halo assembly bias and the tidal anisotropy of the local halo environment
• Measuring the dynamical state of Planck SZ-selected clusters: X-ray peak - BCG offset
• How does the cosmic web impact assembly bias?
• The Three Hundred Project: Backsplash galaxies in simulations of clusters
• Some like it triaxial: the universality of dark matter halo shapes and their evolution along the cosmic time
• On the connectivity of the cosmic web: theory and implications for cosmology and galaxy formation
• A Detection of Dark Matter Halo Ellipticity using Galaxy Cluster Lensing in SDSS
• A weak lensing study of the Coma cluster
• The Three Hundred Project: Dynamical state of galaxy clusters and morphology from multi-wavelength synthetic maps
• Properties of gas phases around cosmic filaments at z=0 in the Illustris-TNG simulation
• The Morphologies and Alignments of Gas, Mass, and the Central Galaxies of CLASH Clusters of Galaxies
• Cosmic web anisotropy is the primary indicator of halo assembly bias
• Do Mergers Spin up Dark Matter Halos?
• The Dynamical State of Dark Matter Haloes in Cosmological Simulations I: Correlations with Mass Assembly History
• Universality of dark matter haloes shape over six decades in mass: Insights from the Millennium XXL and SBARBINE simulations
• Mapping and characterisation of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations
• On the dynamical state of galaxy clusters: insights from cosmological simulations II
• Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142
• The impact of the connectivity of the cosmic web on the physical properties of galaxies at its nodes
• On the shape of dark matter halos from MultiDark Planck simulations
• T-ReX: a graph-based filament detection method
• The Three Hundred Project: The evolution of galaxy cluster density profiles
• A look to the inside of haloes: a characterisation of the halo shape as a function of overdensity in the Planck cosmology
• The ellipticity of galaxy cluster halos from satellite galaxies and weak lensing
• CLUMP-3D. Testing $\Lambda$CDM with galaxy cluster shapes
• Caught in the cosmic web: Environmental effect on halo concentrations, shape, and spin
• Lensing Measurements of the Ellipticity of LRG Dark Matter Halos
• Dynamical state for 964 galaxy clusters from Chandra X-ray images
• Group connectivity in COSMOS: a tracer of mass assembly history
• Shapes and alignments of dark matter haloes and their brightest cluster galaxies in 39 strong lensing clusters
• What Do Dark Matter Properties Tell Us About Their Mass Assembly Histories?
• Correlations between Triaxial Shapes and Formation History of Dark Matter Haloes
• Unusual A2142 supercluster with a collapsing core: distribution of light and mass
• Imprints of Mass Accretion History on the Shape of the Intracluster Medium and the $T_X-M$ Relation
• Convergence properties of halo merger trees; halo and substructure merger rates across cosmic history
• Relating the structure of dark matter halos to their assembly and environment
• On the accretion history of galaxy clusters: temporal and spatial distribution
• Supercluster A2142 and collapse in action - infalling and merging groups and galaxy transformations
• Projected alignment of non-sphericities of stellar, gas, and dark matter distributions in galaxy clusters: analysis of the Horizon-AGN simulation
• Reconciling galaxy cluster shapes, measured by theorists vs observers
• The impact of filamentary accretion of subhaloes on the shape and orientation of haloes
• The clustering of critical points in the evolving cosmic web
• Measuring the surface mass density ellipticity of redMaPPer galaxy clusters using weak-lensing
• The mass-size relation of galaxy clusters
• More connected, more active: galaxy clusters and groups at z~1 and the connection between their quiescent galaxy fractions and large-scale environments

Cited by in corpus (3)

• Relative distribution of dark matter, gas, and stars around cosmic filaments in the IllustrisTNG simulation
• SHAPing the Gas: Understanding Gas Shapes in Dark Matter Haloes with Interpretable Machine Learning
• What to expect from dynamical modelling of cluster haloes I. The information content of different dynamical tracers