Inferring the gravitational potential of the Milky Way with a few precisely measured stars

Abstract

The dark matter halo of the Milky Way is expected to be triaxial and filled with substructure. It is hoped that streams or shells of stars produced by tidal disruption of stellar systems will provide precise measures of the gravitational potential to test these predictions. We develop a method for inferring the Galactic potential with tidal streams based on the idea that the stream stars were once close in phase space. Our method can flexibly adapt to any form for the Galactic potential: it works in phase-space rather than action-space and hence relies neither on our ability to derive actions nor on the integrability of the potential. Our model is probabilistic, with a likelihood function and priors on the parameters. The method can properly account for finite observational uncertainties and missing data dimensions. We test our method on synthetic datasets generated from N-body simulations of satellite disruption in a static, multi-component Milky Way including a triaxial dark matter halo with observational uncertainties chosen to mimic current and near-future surveys of various stars. We find that with just four well-measured stream stars, we can infer properties of a triaxial potential with precisions of order 5-7 percent. Without proper motions we obtain 15 percent constraints on potential parameters and precisions around 25 percent for recovering missing phase-space coordinates. These results are encouraging for the eventual goal of using flexible, time-dependent potential models combined with larger data sets to unravel the detailed shape of the dark matter distribution around the Milky Way.

30 pages, 12 figures, submitted to ApJ

References in corpus (6)

• An Orphan in the "Field of Streams"
• The shapes, orientation, and alignment of Galactic dark matter subhalos
• The mechanics of tidal streams
• The Graininess of Dark Matter Haloes
• Fitting orbits to tidal streams with proper motions
• The Effect of Substructure on Mass Estimates of Galaxies

Cited by in corpus (33)

• Globular Cluster Streams as Galactic High-Precision Scales - The Poster Child Palomar 5
• The shape of the inner Milky Way halo from observations of the Pal 5 and GD-1 stellar streams
• Generation of mock tidal streams
• Dipping Our Toes in the Water: First Models of GD-1 as a Stream
• On feathers, bifurcations and shells: the dynamics of tidal streams across the mass scale
• Dark matter in galaxies
• Joint constraints on the Galactic dark matter halo and Galactic Centre from hypervelocity stars
• Kinematics of the Palomar 5 stellar stream from RR Lyrae stars
• Uncertainties associated with the backward integration of dwarf satellites using simple parametric potentials
• Modeling the gravitational potential of a cosmological dark matter halo with stellar streams
• The twisted dark matter halo of the Milky Way
• An artificial neural network to discover Hypervelocity stars: Candidates in Gaia DR1/TGAS
• Orbital Torus Imaging: Using Element Abundances to Map Orbits and Mass in the Milky Way
• Constraining the Gravitational Potential from the Projected Morphology of Extragalactic Tidal Streams
• Star Formation in Ultrafaint Dwarfs: Continuous or Single-age Bursts?
• The oblateness of the Milky Way dark matter halo from the stellar streams of NGC 3201, M68, and Palomar 5
• A chemo-dynamical link between the Gjöll stream and NGC 3201
• Comparing hypervelocity star populations from the Large Magellanic Cloud and the Milky Way
• The Milky Way, Coming into Focus: Precision Astrometry Probes its Evolution, and its Dark Matter
• Charting Galactic Accelerations with Stellar Streams and Machine Learning
• The Extended Tidal Tails of NGC 7089 (M2)
• Is the vast polar structure of dwarf galaxies a serious problem for lambda cold dark matter?
• Variation in the Stellar Mass Function Along Stellar Streams
• Probing the shape of the Milky Way dark matter halo with hypervelocity stars: a new method
• The Multiple Extended Tidal Tails of NGC 288
• Probing modified Newtonian dynamics with hypervelocity stars
• Building an Acceleration Ladder with Tidal Streams and Pulsar Timing
• A Gravitational Double Scattering Mechanism for Generating High Velocity Objects
• Modeling Tidal Streams and Tidal Tails around Galaxies Using Deep Wendelstein Imaging Data
• Inferring the density and membership of stellar streams with flexible models: The GD-1 stream in Gaia Data Release 3
• The dynamical memory of tidal stellar streams: Joint inference of the Galactic potential and the progenitor of GD-1 with flow matching
• walter: A Tool for Predicting Resolved Stellar Population Observations with Applications to the Roman Space Telescope
• Constraining the population of dark matter halo shapes using hierarchical inference with extragalactic stellar streams