Properties and Origin of Galaxy Velocity Bias in the Illustris Simulation

Abstract

We use the hydrodynamical galaxy formation simulations from the Illustris suite to study the origin and properties of galaxy velocity bias, i.e., the difference between the velocity distributions of galaxies and dark matter inside halos. We find that galaxy velocity bias is a decreasing function of the ratio of galaxy stellar mass to host halo mass. In general, central galaxies are not at rest with respect to dark matter halos or the core of halos, with a velocity dispersion above 0.04 times that of the dark matter. The central galaxy velocity bias is found to be mostly caused by the close interactions between the central and satellite galaxies. For satellite galaxies, the velocity bias is related to their dynamical and tidal evolution history after being accreted onto the host halos. It depends on the time after the accretion and their distances from the halo centers, with massive satellites generally moving more slowly than the dark matter. The results are in broad agreements with those inferred from modeling small-scale redshift-space galaxy clustering data, and the study can help improve models of redshift-space galaxy clustering.

arXiv comment15 pages, 11 figures. Accepted for publication in ApJ

References in corpus (46)

• The Sloan Digital Sky Survey: Technical Summary
• The Seventh Data Release of the Sloan Digital Sky Survey
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• 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
• SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores
• The Dependence of Star Formation History and Internal Structure on Stellar Mass for 10^5 Low-Redshift Galaxies
• Properties of galaxies reproduced by a hydrodynamic simulation
• Introducing the Illustris Project: the evolution of galaxy populations across cosmic time
• Substructures in hydrodynamical cluster simulations
• The Halo Occupation Distribution: Towards an Empirical Determination of the Relation Between Galaxies and Mass
• The merger rate of galaxies in the Illustris Simulation: a comparison with observations and semi-empirical models
• The density and peculiar velocity fields of nearby galaxies
• The Illustris Simulation: Public Data Release
• The Halo Occupation Distribution and the Physics of Galaxy Formation
• Effects of Baryons and Dissipation on the Matter Power Spectrum
• Evolution of the Galaxy - Dark Matter Connection and the Assembly of Galaxies in Dark Matter Halos
• Testing cosmological structure formation using redshift-space distortions
• A fitting formula for the merger timescale of galaxies in hierarchical clustering
• Halo mass function: Baryon impact, fitting formulae and implications for cluster cosmology
• A 2.5% measurement of the growth rate from small-scale redshift space clustering of SDSS-III CMASS galaxies
• The influence of baryons on the clustering of matter and weak lensing surveys
• Galaxy Morphology and Star Formation in the Illustris Simulation at z=0
• Are Brightest Halo Galaxies Central Galaxies?
• The impact of galaxy formation on the total mass, mass profile and abundance of haloes
• The abundance of (not just) dark matter haloes
• Redshift-Space Clustering of SDSS Galaxies --- Luminosity Dependence, Halo Occupation Distribution, and Velocity Bias
• Velocity Bias from the Small Scale Clustering of SDSS-III BOSS Galaxies
• Modelling galaxy clustering: halo occupation distribution versus subhalo matching
• Redshift-Space Distortions with the Halo Occupation Distribution II: Analytic Model
• The effect of baryons on redshift space distortions and cosmic density and velocity fields in the EAGLE simulation
• Are peculiar velocity surveys competitive as a cosmological probe?
• The Phase-Space Parameters of Brightest Halo Galaxies
• The impact of baryonic processes on the two-point correlation functions of galaxies, subhaloes and matter
• Baryon Dynamics, Dark Matter Substructure, and Galaxies
• Galaxy Cluster Mass Estimation from Stacked Spectroscopic Analysis
• The Atacama Cosmology Telescope: Dynamical masses for 44 SZ-selected galaxy clusters over 755 square degrees
• Accurate and Efficient Halo-based Galaxy Clustering Modelling with Simulations
• Modelling The Redshift-Space Three-Point Correlation Function in SDSS-III
• Virial scaling of galaxies in clusters: bright to faint is cool to hot
• Internal kinematics of groups of galaxies in the Sloan Digital Sky Survey data release 7
• Spatial and Dynamical Biases in Velocity Statistics of Galaxies

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• Exploring the squeezed three-point galaxy correlation function with generalized halo occupation distribution models
• The Cluster-EAGLE project: velocity bias and the velocity dispersion - mass relation of cluster galaxies
• Updated Results on the Galaxy-Halo Connection from Satellite Kinematics in SDSS
• Sloshing in its cD halo: MUSE kinematics of the central galaxy NGC 3311
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• Euclid: Early Release Observations -- The intracluster light and intracluster globular clusters of the Perseus cluster
• The MillenniumTNG Project: Inferring cosmology from galaxy clustering with accelerated N-body scaling and subhalo abundance matching
• The Hydra I cluster core - II. Kinematic complexity in a rising velocity dispersion profile around the cD galaxy NGC 3311
• Maturing Satellite Kinematics into a Competitive Probe of the Galaxy-Halo Connection
• Velocity reconstruction in the era of DESI and Rubin (part I): Exploring spectroscopic, photometric & hybrid samples
• Cosmological Information from the Small-scale Redshift Space Distortions
• The Effect of Assembly Bias on Redshift Space Distortions
• 2D k-th nearest neighbor statistics: a highly informative probe of galaxy clustering
• Uneven flows: On cosmic bulk flows, local observers, and gravity
• BASILISK: Bayesian Hierarchical Inference of the Galaxy-Halo Connection using Satellite Kinematics--I. Method and Validation
• Mass accretion rates of the HectoMAP clusters of galaxies
• Tests of Acoustic Scale Shifts in Halo-based Mock Galaxy Catalogues
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• Satellite Galaxies in the Illustris-1 Simulation: Poor Tracers of the Mass Distribution
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