The Dark Disk of the Milky Way

Abstract

Massive satellite accretions onto early galactic disks can lead to the deposition of dark matter in disk-like configurations that co-rotate with the galaxy. This phenomenon has potentially dramatic consequences for dark matter detection experiments. We utilize focused, high-resolution simulations of accretion events onto disks designed to be Galaxy analogues, and compare the resultant disks to the morphological and kinematic properties of the Milky Way's thick disk in order to bracket the range of co-rotating accreted dark matter. We find that the Milky Way's merger history must have been unusually quiescent compared to median LCDM expectations and therefore its dark disk must be relatively small: the fraction of accreted dark disk material near the Sun is about 20% of the host halo density or smaller and the co-rotating dark matter fraction near the Sun, defined as particles moving with a rotational velocity lag less than 50 km/s, is enhanced by about 30% or less compared to a standard halo model. Such a dark disk could contribute dominantly to the low energy (of order keV for a dark matter particle with mass 100 GeV) nuclear recoil event rate of direct dectection experiments, but it will not change the likelihood of detection significantly. These dark disks provide testable predictions of weakly-interacting massive particle dark matter models and should be considered in detailed comparisons to experimental data. Our findings suggest that the dark disk of the Milky Way may provide a detectable signal for indirect detection experiments, contributing up to about 25% of the dark matter self-annihilation signal in the direction of the center of the Galaxy, lending the signal a noticeably oblate morphology.

11 pages, 6 figures, 1 table; submitted to ApJ

References in corpus (9)

• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• Forming Disk Galaxies in Lambda CDM Simulations
• Thin, thick and dark discs in LCDM
• Phase-space structure in the local dark matter distribution and its signature in direct detection experiments
• Can Gas prevent the Destruction of Thin Stellar Discs by Minor Mergers?
• Galactic Substructure and Direct Detection of Dark Matter
• The Destruction of Thin Stellar Disks Via Cosmologically Common Satellite Accretion Events
• Detecting the Milky Way's Dark Disk
• Dark matter in the solar system I: The distribution function of WIMPs at the Earth from solar capture

Cited by in corpus (77)

• The Local Dark Matter Density
• Annual Modulation of Dark Matter: A Review
• Determination of the Local Dark Matter Density in our Galaxy
• A review of the discovery reach of directional Dark Matter detection
• "Galaxy," Defined
• Search for annihilating dark matter in the Sun with 3 years of IceCube data
• Revealing the Dark Matter Halo with Axion Direct Detection
• Dark matter local density determination: recent observations and future prospects
• On the estimation of the Local Dark Matter Density using the rotation curve of the Milky Way
• Modulation Effects in Dark Matter-Electron Scattering Experiments
• Dark Matter Direct Detection Signals inferred from a Cosmological N-body Simulation with Baryons
• Robust implications on Dark Matter from the first FERMI sky gamma map
• Kinematical and chemical vertical structure of the Galactic thick disk II. A lack of dark matter in the solar neighborhood
• Astrophysical uncertainties on direct detection experiments
• Simulated Milky Way analogues: implications for dark matter direct searches
• The Distribution of Dark Matter in the Milky Way's Disk
• Updated global fits of the cMSSM including the latest LHC SUSY and Higgs searches and XENON100 data
• Astrophysical uncertainties on the local dark matter distribution and direct detection experiments
• Simulated Milky Way analogues: implications for dark matter indirect searches
• Effect of Gravitational Focusing on Annual Modulation in Dark-Matter Direct-Detection Experiments
• Exothermic Double-Disk Dark Matter
• Dependence of direct detection signals on the WIMP velocity distribution
• Structure Formation and Exotic Compact Objects in a Dissipative Dark Sector
• Heated Disc Stars in the Stellar Halo
• Lessons from the Auriga discs: The hunt for the Milky Way's ex-situ disc is not yet over
• The Gaia-ESO Survey: a quiescent Milky Way with no significant dark/stellar accreted disc
• Dark-Matter Harmonics Beyond Annual Modulation
• WIMP astronomy and particle physics with liquid-noble and cryogenic direct-detection experiments
• Directional axion detection
• Annual Modulation in Direct Dark Matter Searches
• Dark Matter Direct Search Rates in Simulations of the Milky Way and Sagittarius Stream
• Quantifying Astrophysical Uncertainties on Dark Matter Direct Detection Results
• Impact of Dark Matter Velocity Distributions on Capture Rates in the Sun
• Kinematical and chemical vertical structure of the Galactic thick disk I. Thick disk kinematics
• 10 GeV dark matter candidates and cosmic-ray antiprotons
• Weighing the Galactic disk using phase-space spirals II. Most stringent constraints to a thin dark disk using Gaia EDR3
• Implications of hydrodynamical simulations for the interpretation of direct dark matter searches
• Dark Photons from the Center of the Earth: Smoking-Gun Signals of Dark Matter
• No evidence for a dark matter disk within 4 kpc from the Galactic plane
• Improved determination of the WIMP mass from direct detection data
• Getting the astrophysics and particle physics of dark matter out of next-generation direct detection experiments
• Tidal Dwarf Galaxies and missing baryons
• Probing the Local Velocity Distribution of WIMP Dark Matter with Directional Detectors
• Chasing Accreted Structures within Gaia DR2 using Deep Learning
• Measuring the local matter density using Gaia DR2
• New Limits on Charged Dark Matter from Large-Scale Coherent Magnetic Fields
• Asymmetric Dark Matter May Alter the Evolution of Low-mass Stars and Brown Dwarfs
• The hunt for the Milky Way's accreted disc
• Dark Matter Trapping by Stellar Bars: The Shadow Bar
• Gravitational Focusing of Wave Dark Matter
• A non-parametric method for measuring the local dark matter density
• Solar WIMPs Unraveled: Experiments, astrophysical uncertainties, and interactive Tools
• Fermi-LAT kills dark matter interpretations of AMS-02 data. Or not?
• On local dark matter density
• Optimized velocity distributions for direct dark matter detection
• A novel approach to derive halo-independent limits on dark matter properties
• Is the Dark Disc contribution to Dark Matter Signals important ?
• Weighing the Galactic disk using phase-space spirals I. Tests on one-dimensional simulations
• Weighing the Galactic disk in sub-regions of the solar neighbourhood using Gaia DR2
• The low abundance and insignificance of dark discs in simulated Milky Way galaxies
• The Dark Matter Density in the Solar Neighborhood reconsidered
• Is a co-rotating Dark Disk a threat to Dark Matter Directional Detection ?
• Informing dark matter direct detection limits with the ARTEMIS simulations
• New Dissipation Mechanisms from Multi-level Dark Matter Scattering
• Dynamics of Stellar Disk Tilting from Satellite Mergers
• Dark matter local density determination based on recent observations
• The Dynamical Response of Dark Matter to Galaxy Evolution Affects Direct-Detection Experiments
• Dark Matter Studies Entrain Nuclear Physics
• The 11-years solar cycle as the manifestation of the dark Universe
• Gravitational Focusing and Substructure Effects on the Rate Modulation in Direct Dark Matter Searches
• Development of dark disk model of positron anomaly origin
• High-Resolution Chemical Abundances of the Nyx Stream
• Measuring the Matter Density of the Galactic Disk Using Stellar Streams
• The Dark Universe is not invisible
• The Futile Search for Galactic Disk Dark Matter
• AMS-02 fits Dark Matter
• TeV dark matter in the disk