The Milky Way Tomography with SDSS. V. Mapping the Dark Matter Halo

Abstract

We present robust constraints from the Sloan Digital Sky Survey (SDSS) on the shape and distribution of the dark matter halo within the Milky Way (MW). Using the number density distribution and kinematics of SDSS halo stars, we probe the dark matter distribution to heliocentric distances exceeding 10 kpc and galactocentric distances exceeding 20 kpc. Our analysis utilizes Jeans equations to generate two-dimensional acceleration maps throughout the volume; this approach is thoroughly tested on a cosmologically derived N-body+SPH simulation of a MW-like galaxy. We show that the known accelerations (gradients of the gravitational potential) can be successfully recovered in such a realistic system. Leveraging the baryonic gravitational potential derived by Bovy & Rix (2013), we show that the gravitational potential implied by the SDSS observations cannot be explained, assuming Newtonian gravity, by visible matter alone: the gravitational force experienced by stars at galactocentric distances of 20 kpc is as much as three times stronger than what can be attributed to purely visible matter. We also show that the SDSS data provide a strong constraint on the shape of the dark matter halo potential. Within galactocentric distances of 20 kpc, the dark matter halo potential is well described as an oblate halo with axis ratio qDM=0.7+/-0.1; this corresponds to an axis ratio qDM=0.4+/-0.1 for the dark matter density distribution. Because of our precise two-dimensional measurements of the acceleration of the halo stars, we can reject several MOND models as an explanation of the observed behavior.

arXiv comment15 pages, 21 figures, accepted to ApJ. If viewing using Preview, some figures may appear blurry. If possible, please view using Adobe PDF Viewer

References in corpus (66)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• The Sloan Digital Sky Survey: Technical Summary
• The Milky Way Tomography with SDSS: I. Stellar Number Density Distribution
• SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
• Tracing Galaxy Formation with Stellar Halos I: Methods
• The Inner Structure of LambdaCDM Halos I: A Numerical Convergence Study
• Direct constraints on the dark matter self-interaction cross-section from the merging galaxy cluster 1E0657-56
• Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations--I. Isolated Galaxies
• The Milky Way's Circular Velocity Curve to 60 kpc and an Estimate of the Dark Matter Halo Mass from Kinematics of ~2400 SDSS Blue Horizontal Branch Stars
• Modified Newtonian Dynamics as an Alternative to Dark Matter
• Gasoline: An adaptable implementation of TreeSPH
• LCDM-based models for the Milky Way and M31 I: Dynamical Models
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The Sagittarius Dwarf Galaxy: a Model for Evolution in a Triaxial Milky Way Halo
• A direct dynamical measurement of the Milky Way's disk surface density profile, disk scale length, and dark matter profile at 4 kpc < R < 9 kpc
• Great Circle tidal streams: evidence for a nearly spherical massive dark halo around the Milky Way
• The Aquila comparison Project: The Effects of Feedback and Numerical Methods on Simulations of Galaxy Formation
• The spatial structure of mono-abundance sub-populations of the Milky Way disk
• The Enrichment of the Intergalactic Medium with Adiabatic Feedback I: Metal Cooling and Metal Diffusion
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• Constraining the Milky Way potential with a 6-D phase-space map of the GD-1 stellar stream
• The Dual Origin of Stellar Halos
• Modified Newtonian Dynamics in the Milky Way
• Detection of a 63 Degree Cold Stellar Stream in the Sloan Digital Sky Survey
• Baryons Matter: Why Luminous Satellite Galaxies Have Reduced Central Masses
• On the local dark matter density
• The local density of matter mapped by Hipparcos
• The Milky Way stellar halo out to 40 kpc : Squashed, broken but smooth
• The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way
• The Milky Way has no thick disk
• Substructure revealed by RR Lyraes in SDSS Stripe 82
• The local surface density of disc matter mapped by Hipparcos
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Light Curve Templates and Galactic Distribution of RR Lyrae Stars from Sloan Digital Sky Survey Stripe 82
• The Milky Way Tomography with SDSS: III. Stellar Kinematics
• Tidal Streams as Probes of the Galactic Potential
• Made-to-measure N-body systems
• The Causes of Halo Shape Changes Induced by Cooling Baryons: Disks Versus Substructures
• Reproducing the Stellar Mass/Halo Mass Relation in Simulated LCDM Galaxies: Theory vs Observational Estimates
• The Case for the Dual Halo of the Milky Way
• Implementing Molecular Hydrogen in Hydrodynamic Simulations of Galaxy Formation
• The Shape and Profile of the Milky Way Halo as Seen by the CFHT Legacy Survey
• A new determination of the local dark matter density from the kinematics of K dwarfs
• The Gravitational Potential Near the Sun From SEGUE K-dwarf Kinematics
• Constraints on the shape of the Milky Way dark matter halo from the Sagittarius stream
• Misaligned Angular Momentum in Hydrodynamic Cosmological Simulations: Warps, Outer Discs, and Thick Discs
• Galactic Stellar Populations in the Era of SDSS and Other Large Surveys
• MOND laws of galactic dynamics
• Kinematical and chemical vertical structure of the Galactic thick disk II. A lack of dark matter in the solar neighborhood
• The vertical motions of mono-abundance sub-populations in the Milky Way disk
• Dynamics of the Magellanic Clouds in a LCDM Universe
• Insight Into the Formation of the Milky Way Through Cold Halo Substructure. I. The ECHOS of Milky Way Formation
• Interpreting the Evolution of the Size - Luminosity Relation for Disk Galaxies from Redshift 1 to the Present
• Slicing and dicing the Milky Way disk in SDSS
• Velocity Dispersion Profile of the Milky Way Halo
• Revealing Substructure in the Galactic Halo - The SEKBO RR Lyrae Survey
• Vertical distribution of Galactic disk stars : II. The surface mass density in the Galactic plane
• Gaps in the GD-1 Star Stream
• Milky Way Tomography IV: Dissecting Dust
• Tailoring triaxial N-body models via a novel made-to-measure method
• Probing the shape and history of the Milky Way halo with orbital spectral analysis
• Dynamics for Galactic Archaeology
• Insight Into the Formation of the Milky Way Through Cold Halo Substructure. II. The Elemental Abundances of ECHOS
• Constraining the Galactic potential via action-based distribution functions for mono-abundance stellar populations
• Constraints on the Shape of the Milky Way Dark Matter Halo from Jeans Equations Applied to SDSS Data

Cited by in corpus (45)

• The mass distribution and gravitational potential of the Milky Way
• Co-formation of the Galactic disc and the stellar halo
• The shape of the inner Milky Way halo from observations of the Pal 5 and GD-1 stellar streams
• Dynamical constraints on the dark matter distribution in the Milky Way
• The mass of our Milky Way
• Constraining the Milky Way Halo Potential with the GD-1 stellar stream
• The Diversity and Variability of Star Formation Histories in Models of Galaxy Evolution
• The Gravitational Force Field of the Galaxy Measured From the Kinematics of RR Lyrae in Gaia
• The information content in cold stellar streams
• Inside Out and Upside-Down: The Roles of Gas Cooling and Dynamical Heating in Shaping the Stellar Age-Velocity Relation
• Assessing Astrophysical Uncertainties in Direct Detection with Galaxy Simulations
• The impact of baryons on the direct detection of dark matter
• Bayesian Mass Estimates of the Milky Way II: The dark and light sides of parameter assumptions
• The effects of host galaxy properties on merging compact binaries detectable by LIGO
• The Role of Baryons in Creating Statistically Significant Planes of Satellites around Milky Way-Mass Galaxies
• Milky Way total Mass derived by Rotation Curve and Globular Cluster kinematics from Gaia EDR3
• Dark Matter Interpretation of the Fermi-LAT Observations Toward the Outer Halo of M31
• Is the Dark Halo of the Milky Way Prolate?
• Action-based distribution function modelling for constraining the shape of the Galactic dark matter halo
• Testing modified Newtonian dynamics in the Milky Way
• The dark matter profile of the Milky Way: a non-parametric reconstruction
• Stellar Velocity Dispersion and Anisotropy of the Milky Way Inner Halo
• $\text{galkin}$: a new compilation of the Milky Way rotation curve data
• Testing Dark Matter and Modifications to Gravity using Local Milky Way Observables
• The Milky Way's Hot Gas Kinematics: Signatures in Current and Future OVII Absorption Line Observations
• Stellar Accelerations and the Galactic Gravitational Field
• On measuring the Galactic dark matter halo with hypervelocity stars
• Shapes of Milky-Way-Mass Galaxies with Self-Interacting Dark Matter
• Impact of the Galactic Disk and Large Magellanic Cloud on the Trajectories of Hypervelocity Stars Ejected from the Galactic Center
• The oblateness of the Milky Way dark matter halo from the stellar streams of NGC 3201, M68, and Palomar 5
• Around The Way: Testing $\Lambda$CDM with Milky Way Stellar Stream Constraints
• The road to MOND--a novel perspective
• A slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp
• Measuring Galactic Dark Matter through Unsupervised Machine Learning
• Axion Structure Formation I: The Co-motion Picture
• Probing the shape of the Milky Way dark matter halo with hypervelocity stars: a new method
• Probing modified Newtonian dynamics with hypervelocity stars
• Detecting Triaxiality in the Galactic Dark Matter Halo through Stellar Kinematics II: Dependence on Dark Matter and Gravity Nature
• The imprint of dark matter on the Galactic acceleration field
• Stellar Migration and Chemical Enrichment in the Milky Way Disc: A Hybrid Model
• A Vertically Orientated Dark Matter Halo Marks a Flip of the Galactic Disk
• Uncover 3D Dark Matter Distribution of the Milky Way by an Empirical Triaxial Orbit-Superposition Model: Method Validation
• Charting galactic accelerations II: how to 'learn' accelerations in the solar neighbourhood
• Validation of the Bond et al. (2010) SDSS-derived kinematic models for the Milky Way's disk and halo stars with Gaia Data Release 3 proper motion and radial velocity data
• Primordial helium-3 redux: The helium isotope ratio of the Orion nebula