The Immitigable Nature of Assembly Bias: The Impact of Halo Definition on Assembly Bias

Abstract

Dark matter halo clustering depends not only on halo mass, but also on other properties such as concentration and shape. This phenomenon is known broadly as assembly bias. We explore the dependence of assembly bias on halo definition, parametrized by spherical overdensity parameter, $\Delta$. We summarize the strength of concentration-, shape-, and spin-dependent halo clustering as a function of halo mass and halo definition. Concentration-dependent clustering depends strongly on mass at all $\Delta$. For conventional halo definitions ($\Delta \sim 200\mathrm{m}-600\mathrm{m}$), concentration-dependent clustering at low mass is driven by a population of haloes that is altered through interactions with neighbouring haloes. Concentration-dependent clustering can be greatly reduced through a mass-dependent halo definition with $\Delta \sim 20\mathrm{m}-40\mathrm{m}$ for haloes with $M_{200\mathrm{m}}\lesssim 10^{12}{h}^{-1}{\mathrm{M}}_{\odot }$. Smaller $\Delta$ implies larger radii and mitigates assembly bias at low mass by subsuming altered, so-called backsplash haloes into now larger host haloes. At higher masses ($M_{200\mathrm{m}}\gtrsim 10^{13}{h}^{-1}{\mathrm{M}}_{\odot }$) larger overdensities, $\Delta \gtrsim 600\mathrm{m}$, are necessary. Shape- and spin-dependent clustering are significant for all halo definitions that we explore and exhibit a relatively weaker mass dependence. Generally, both the strength and the sense of assembly bias depend on halo definition, varying significantly even among common definitions. We identify no halo definition that mitigates all manifestations of assembly bias. A halo definition that mitigates assembly bias based on one halo property (e.g., concentration) must be mass dependent. The halo definitions that best mitigate concentration-dependent halo clustering do not coincide with the expected average splashback radii at fixed halo mass.

19 pages, 13 figures. Updated to published version. Main result summarized in Figure 10

References in corpus (25)

• The NumPy array: a structure for efficient numerical computation
• Galaxy Evolution from Halo Occupation Distribution Modeling of DEEP2 and SDSS Galaxy Clustering
• Properties of Dark Matter Haloes in Clusters, Filaments, Sheets and Voids
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• Rotation-Dependent Catastrophic Disruption of Gravitational Aggregates
• Assembly bias in the clustering of dark matter haloes
• A universal model for halo concentrations
• Halo assembly bias and its effects on galaxy clustering
• The Evolution of Dark Matter Halo Properties in Clusters, Filaments, Sheets and Voids
• Towards a Concordant Model of Halo Occupation Statistics
• The Excursion Set Theory of Halo Mass Functions, Halo Clustering, and Halo Growth
• Splashback in accreting dark matter halos
• The Unorthodox Orbits of Substructure Halos
• On Halo Formation Times and Assembly Bias
• Effects of AGN feedback on LCDM galaxies
• A Consistent Study of Metallicity Evolution at 0.8 < z < 2.6
• Luminosity and redshift dependent quasar clustering
• The splashback radius of halos from particle dynamics. II. Dependence on mass, accretion rate, redshift, and cosmology
• Environmental Dependence of Cold Dark Matter Halo Formation
• Splashback Shells of Cold Dark Matter Halos
• Halo Histories vs. Galaxy Properties at z=0 II: Large-Scale Galactic Conformity
• The nature of assembly bias - I. Clues from a LCDM cosmology
• On the evidence for large-scale galactic conformity in the local Universe
• The Tidal Streams of Disrupting Subhaloes in Cosmological Dark Matter Haloes
• The nature of assembly bias - II. Halo spin

Cited by in corpus (36)

• Core Cosmology Library: Precision Cosmological Predictions for LSST
• Spatial Clustering of Dark Matter Halos: Secondary Bias, Neighbor Bias, and the Influence of Massive Neighbors on Halo Properties
• Dissecting and Modelling Galaxy Assembly Bias
• The Three Causes of Low-Mass Assembly Bias
• The Evolution of Assembly Bias
• Cosmic web anisotropy is the primary indicator of halo assembly bias
• Evidence for galaxy assembly bias in BOSS CMASS redshift-space galaxy correlation function
• The Aemulus Project V: Cosmological constraint from small-scale clustering of BOSS galaxies
• How Biased Are Halo Properties in Cosmological Simulations?
• Exploring the squeezed three-point galaxy correlation function with generalized halo occupation distribution models
• Flybys, orbits, splashback: subhalos and the importance of the halo boundary
• How Accurately Can We Detect the Splashback Radius of Dark Matter Halos and its Correlation With Accretion Rate?
• New perspectives on the BOSS small-scale lensing discrepancy for the Planck $\Lambda$CDM Cosmology
• Aemulus $\nu$: Precise Predictions for Matter and Biased Tracer Power Spectra in the Presence of Neutrinos
• Updated Results on the Galaxy-Halo Connection from Satellite Kinematics in SDSS
• Detection of anisotropic galaxy assembly bias in BOSS DR12
• The Secondary Spin Bias of Dark Matter Haloes
• Cosmology with Stacked Cluster Weak Lensing and Cluster-Galaxy Cross-Correlations
• The splashback radius of halos from particle dynamics: III. Halo catalogs, merger trees, and host-subhalo relations
• Galaxy assembly bias of central galaxies in the Illustris simulation
• Predictably Missing Satellites: Subhalo Abundance in Milky Way-like Halos
• The physical origins of low-mass spin bias
• How to Optimally Constrain Galaxy Assembly Bias: Supplement Projected Correlation Functions with Count-in-cells Statistics
• On the prospect of using the maximum circular velocity of halos to encapsulate assembly bias in the galaxy-halo connection
• Some assembly required: assembly bias in massive dark matter halos
• Observational Measures of Halo Properties Beyond Mass
• Clustering Constraints on the Relative Sizes of Central and Satellite Galaxies
• Main Sequence Scatter is Real: The Joint Dependence of Galaxy Clustering on Star Formation and Stellar Mass
• Connections between galaxy properties and halo formation time in the cosmic web
• BASILISK: Bayesian Hierarchical Inference of the Galaxy-Halo Connection using Satellite Kinematics--I. Method and Validation
• Toward Accurate Modeling of Galaxy Clustering on Small Scales: Halo Model Extensions and Lingering Tension
• PRIMUS: Clustering of Star-forming and Quiescent Central Galaxies at $0.2<z<0.9$
• The SRG/eROSITA All-Sky Survey: Exploring halo assembly bias with X-ray selected superclusters
• Distinguishing Orbiting and Infalling Dark Matter Particles with Machine Learning
• On the Assembly Bias of Cool Core Clusters Traced by H$\alpha$ Nebulae
• Correlation between Outlying Halo Abundance and Host Halo Properties