The Tessellation-Level-Tree: characterising the nested hierarchy of density peaks and their spatial distribution in cosmological N-body simulations

Abstract

We use the Millennium and Millennium-II simulations to illustrate the Tessellation-Level-Tree (TLT), a hierarchical tree structure linking density peaks in a field constructed by voronoi tessellation of the particles in a cosmological N-body simulation. The TLT uniquely partitions the simulation particles into disjoint subsets, each associated with a local density peak. Each peak is a subpeak of a unique higher peak. The TLT can be persistence filtered to suppress peaks produced by discreteness noise. Thresholding a peak's particle list at $\sim 80⟨\rho ⟩$ results in a structure similar to a standard friend-of-friends halo and its subhaloes. For thresholds below $\sim 7⟨\rho ⟩$, the largest structure percolates and is much more massive than other objects. It may be considered as defining the cosmic web. For a threshold of $5⟨\rho ⟩$, it contains about half of all cosmic mass and occupies $\sim 1\%$ of all cosmic volume; a typical external point is then $\sim 7h^{-1}\mathrm{Mpc}$ from the web. We investigate the internal structure and clustering of TLT peaks. Defining the saddle point density ${\rho }_{\lim }$ as the density at which a peak joins its parent peak, we show the median value of ${\rho }_{\lim }$ for FoF-like peaks to be similar to the density threshold at percolation. Assembly bias as a function of ${\rho }_{\lim }$ is stronger than for any known internal halo property. For peaks of group mass and below, the lowest quintile in ${\rho }_{\lim }$ has $b\approx 0$, and is thus uncorrelated with the mass distribution.

arXiv comment21 pages, 18 figures, version as accepted by MNRAS

References in corpus (53)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• A Universal Density Profile from Hierarchical Clustering
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Large scale bias and the peak background split
• Populating a cluster of galaxies - I. Results at z=0
• E pur si muove: Galiliean-invariant cosmological hydrodynamical simulations on a moving mesh
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Simulating Galaxy Formation with the IllustrisTNG Model
• An analytic model for the spatial clustering of dark matter haloes
• The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores
• Dark Energy Survey Year 1 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
• How Filaments are Woven into the Cosmic Web
• Resolving Cosmic Structure Formation with the Millennium-II Simulation
• The statistics of LCDM Halo Concentrations
• Merger rates in hierarchical models of galaxy formation. II: Comparison with N-body simulations
• The age dependence of halo clustering
• The persistent cosmic web and its filamentary structure I: Theory and implementation
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• The Dependence of Halo Clustering on Halo Formation History, Concentration, and Occupation
• The Horizon-AGN simulation: morphological diversity of galaxies promoted by AGN feedback
• Dark matter and cosmic structure
• Assembly bias in the clustering of dark matter haloes
• ZOBOV: a parameter-free void-finding algorithm
• Tracing the cosmic web
• The MassiveBlack-II Simulation: The Evolution of Halos and Galaxies to z~0
• The origin and implications of dark matter anisotropic cosmic infall on ~L* haloes
• A Cosmic Watershed: the WVF Void Detection Technique
• The persistent cosmic web and its filamentary structure II: Illustrations
• Halo Assembly Bias in Hierarchical Structure Formation
• Galaxy evolution in the metric of the Cosmic Web
• Structure Finding in Cosmological Simulations: The State of Affairs
• Tracing the Dark Matter Sheet in Phase Space
• The overdensity and masses of the friends-of-friends halos and universality of the halo mass function
• The Cosmic Web: Geometric Analysis
• HBT+: an improved code for finding subhalos and building merger trees in cosmological simulations
• Voids in massive neutrino cosmologies
• Massive Neutrinos Leave Fingerprints on Cosmic Voids
• Assembly bias and the dynamical structure of dark matter halos
• Resolving Subhaloes' Lives with the Hierarchical Bound-Tracing Algorithm
• The Topology of the Cosmic Web in Terms of Persistent Betti Numbers
• ZOMG-I. How the cosmic web inhibits halo growth and generates assembly bias
• VOBOZ: An Almost-Parameter-Free Halo-Finding Algorithm
• Cosmic web anisotropy is the primary indicator of halo assembly bias
• Large-scale assembly bias of dark matter halos
• The Birth and Growth of Neutralino Haloes
• Stochastic Homology of Gaussian vs. non-Gaussian Random Fields: Graphs towards Betti Numbers and Persistence Diagrams
• Cosmological N-Body simulation: Techniques, Scope and Status
• The median density of the Universe
• Exploring the non-linear density field in the Millennium simulations with tessellations - I. The probability distribution function
• Massive Gravity wrapped in the Cosmic Web
• Gravitational N-body Simulations
• An observational signal of the void shape correlation and its link to the cosmic web

Cited by in corpus (6)

• Volume Statistics as a Probe of Large-Scale Structure
• Opening Reionization: Quantitative Morphology of the Epoch of Reionization and Its Connection to the Cosmic Density Field
• The Voronoi tessellation method in astronomy
• Position-dependent Voronoi probability distribution functions for matter and halos
• The Boosted Potential
• The relation of galaxies and dark matter haloes to the filamentary cosmic web