Are Halos of Collisionless Cold Dark Matter Collisionless?

Abstract

Much recent discussion about dark matter has been centered on two seemingly independent problems: the abundance of substructure in dark matter halos, and the cuspiness of the halos' inner density profile. We explore possible connections between the two problems by studying the gravitational scattering effects due to subhalos on the phase-space distribution of dark matter particles in the main halos. Our series of controlled numerical experiments indicates that the number and mass density of subhalos can be high enough to cause the collisionless dark matter particles in the inner part of a main halo to diffuse, flattening the main halo's inner cusp within a few dynamical times. Depending on the masses and concentration of the subhalos, the inner density profile of the whole system (main plus sub halos) can either steepen or flatten. Subhalo accretion can therefore introduce significant scatter in the inner density profiles of dark matter halos, offering a possible explanation for the range of profiles seen in both observations and cosmological simulations.

4 pages, 3 figures. Phys Rev Lett, in press on May 14

References in corpus (15)

• A Universal Density Profile from Hierarchical Clustering
• Where are the missing galactic satellites?
• GADGET: A code for collisionless and gasdynamical cosmological simulations
• Halo Formation in Warm Dark Matter Models
• The Inner Structure of LambdaCDM Halos III: Universality and Asymptotic Slopes
• Density profiles and substructure of dark matter halos: converging results at ultra-high numerical resolution
• Substructure and halo density profiles in a Warm Dark Matter Cosmology
• The Dark Matter Distribution in Disk Galaxies
• Substructures in Cold Dark Matter Haloes
• Generating Equilibrium Dark Matter Halos: Inadequacies of the Local Maxwellian Approximation
• Flat-Cored Dark Matter in Cuspy Clusters of Galaxies
• Density profiles of LCDM clusters
• Dark matter in Draco and the Local Group: Implications for direct detection experiments
• Major Mergers of Galaxy Haloes: Cuspy or Cored Inner Density Profile?
• Dark-Halo Cusp: Asymptotic Convergence

Cited by in corpus (56)

• Galaxy Bimodality due to Cold Flows and Shock Heating
• Secular Evolution in Disk Galaxies
• High-Resolution Measurements of the Halos of Four Dark Matter-Dominated Galaxies: Deviations from a Universal Density Profile
• The Density Profiles of Massive, Relaxed Galaxy Clusters. I. The Total Density Over Three Decades in Radius
• A Revised Model for the Formation of Disk Galaxies: Low Spin and Dark-Halo Expansion
• Small scale problems of the $\Lambda$CDM model: a short review
• Forming Early-Type Galaxies in LambdaCDM Simulations -I. Assembly histories
• Angular Momentum Transfer in Dark Matter Halos: Erasing the Cusp
• Core creation in galaxies and haloes via sinking massive objects
• The Distribution of Dark Matter Over 3 Decades in Radius in the Lensing Cluster Abell 611
• Dark matter halos of massive elliptical galaxies at $z\sim 0.2$ are well described by the Navarro-Frenk-White profile
• The Robustness of Dark Matter Density Profiles in Dissipationless Mergers
• Strong Lensing in Abell 1703: Constraints on the Slope of the Inner Dark Matter Distribution
• The Rotation Velocity Attributable to Dark Matter at Intermediate Radii in Disk Galaxies
• On the Structure of Dark Matter Halos at the Damping Scale of the Power Spectrum with and without Relict Velocities
• Rotation curves of high-resolution LSB and SPARC galaxies with fuzzy and multistate (ultra-light boson) scalar field dark matter
• Galactic cannibalism and CDM density profiles
• On the Density profile slope of Clusters of Galaxies
• Active galactic nuclei and massive galaxy cores
• A unified solution to the small scale problems of the $\Lambda$CDM model
• The Cusp/Core problem: supernovae feedback versus the baryonic clumps and dynamical friction model
• Dissipational versus Dissipationless Galaxy Formation and the Dark Matter Content of Galaxies
• Project Dinos I: A joint lensing-dynamics constraint on the deviation from the power law in the mass profile of massive ellipticals
• Halo density reduction by baryonic settling?
• Deadly dark matter cusps vs faint and extended star clusters: Eridanus II and Andromeda XXV
• Satellite Accretion Onto Massive Galaxies With Central Black Holes
• A unified solution to the small scale problems of the $\Lambda$CDM model II: introducing parent-satellite interaction
• Precision Cosmology
• Moderate Steepening of Galaxy Cluster Dark Matter Profiles by Baryonic Pinching
• Re-examining the Too-Big-To-Fail Problem for Dark Matter Haloes with Central Density Cores
• Slow evolution of elliptical galaxies induced by dynamical friction III. Role of density concentration and pressure anisotropy
• Core Formation in High-z Massive Haloes: Heating by Post Compaction Satellites and Response to AGN Outflows
• The First Billion Years project: dark matter haloes going from contraction to expansion and back again
• Cosmological Simulations of Massive Compact High-z Galaxies
• Energy transfer from baryons to dark matter as a unified solution to small-scale structure issues of the $\Lambda$CDM model
• Slow evolution of elliptical galaxies induced by dynamical friction
• Dark Matter Subhalos in the Ursa Minor Dwarf Galaxy
• On the dark matter haloes inner structure and galaxy morphology
• Non-sphericity of ultralight axion dark matter haloes in the Galactic dwarf spheroidal galaxies
• The Dark Halo of NGC 5963 as a Constraint on Dark Matter Self-Interaction at the Low Velocity Regime
• Gravitational collapse in an expanding background and the role of substructure II: Excess power at small scales and its effect of collapse of structures at larger scales
• On the dwarf galaxies rotation curves diversity problem
• Gravitational collapse in an expanding background and the role of substructure I: Planar collapse
• Effect of small scale density perturbations on the formation of dark matter halo profiles
• Constraining Ultra-light Axions with Galaxy Cluster Number Counts
• Flattening of dark matter cusps during mergers: model of M31
• Simulation-guided galaxy evolution inference: A case study with strong lensing galaxies
• Restudy on Dark Matter Time-Evolution in the Littlest Higgs model with T-parity
• Cluster density slopes from Dark Matter-Baryons Energy Transfer
• A Physical Bias in Cosmological Simulations
• On the origin of transient features in cosmological N-Body Simulations
• Correlations in the matter distribution in CLASH galaxy clusters
• Detecting a physical difference between the CDM halos in simulation and in nature
• Dark Matter Density in Disk Galaxies
• Associated production of a photon with dark matter pair at the ILC within the Littlest Higgs model with T-parity
• A Mass Dependent Density Profile from Dwarfs to Clusters