Quantifying the influence of bars on action-based dynamical modelling of disc galaxies
arXiv:2212.06184 · doi:10.1093/mnras/stad1525
Abstract
Action-based dynamical modelling, using stars as dynamical tracers, is an excellent diagnostic to estimate the underlying axisymmetric matter distribution of the Milky Way. However, the Milky Way's bar causes non-axisymmetric resonance features in the stellar disc. Using Roadmapping (an action-based dynamical modelling framework to estimate the gravitational potential and the stellar distribution function), we systematically quantify the robustness of action-based modelling in the presence of a bar. We construct a set of test-particle simulations of barred galaxies (with varying bar properties), and apply Roadmapping to different survey volumes (with varying azimuthal position, size) drawn from these barred models. For realistic bar parameters, the global potential parameters are still recovered to within ~ 1 - 17 percent. However, with increasing bar strength, the best-fit values of the parameters progressively deviate from their true values. This happens due to a combination of radial heating, radial migration, and resonance overlap phenomena in our bar models. Furthermore, the azimuthal location and the size of the survey volumes play important roles in the successful recovery of the parameters. Survey volumes along the bar major axis produce larger (relative) errors in the best-fit parameter values. In addition, the potential parameters are better recovered for survey volumes with larger spatial coverage. As the Sun is located just ~ 28 - 33 degrees behind the bar's major axis, an estimate for the bar-induced systematic bias -- as provided by this study -- is therefore crucial for future modelling attempts of the Milky Way.
arXiv comment18 pages, 2 tables, 11 figures (including appendix), accepted for publication in MNRAS
References in corpus (81)
- emcee: The MCMC Hammer
- The Structure of Cold Dark Matter Halos
- The Galaxy in Context: Structural, Kinematic and Integrated Properties
- galpy: A Python Library for Galactic Dynamics
- Trigonometric Parallaxes of High Mass Star Forming Regions: the Structure and Kinematics of the Milky Way
- SEGUE: A Spectroscopic Survey of 240,000 stars with g=14-20
- Radial Mixing in Galactic Discs
- Chemical evolution with radial mixing
- Constraints from Dynamical Friction on the Dark Matter Content of Barred Galaxies
- A dynamically young and perturbed Milky Way disk
- The Effect of the Outer Lindblad Resonance of the Galactic Bar on the Local Stellar Velocity Distribution
- Riding the Spiral Waves: Implications of Stellar Migration for the Properties of Galactic Disks
- 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
- The spatial structure of mono-abundance sub-populations of the Milky Way disk
- Gaia Data Release 2: Mapping the Milky Way disc kinematics
- Mapping the Three-Dimensional Density of the Galactic Bulge with VVV Red Clump Stars
- Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
- The Structure of the Milky Way's Bar Outside the Bulge
- The photometric structure of the inner Galaxy
- On the local dark matter density
- On Galactic density modeling in the presence of dust extinction
- Actions for axisymmetric potentials
- The Milky Way's Stellar Disk
- Global properties of the HI distribution in the outer Milky Way
- Gas Dynamics in the Milky Way: Second Pattern Speed and Large-Scale Morphology
- Life in the fast lane: a direct view of the dynamics, formation, and evolution of the Milky Way's bar
- Constraining the Galaxy's dark halo with RAVE stars
- Made-to-measure N-body systems
- Distribution functions for the Milky Way
- Radial Migration in Disk Galaxies I: Transient Spiral Structure and Dynamics
- Vertical disc heating in Milky Way-sized galaxies in a cosmological context
- 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
- Detection of the old stellar component of the major Galactic bar
- The pattern speed of the Milky Way bar from transverse velocities
- Models of our Galaxy II
- NMAGIC: Fast Parallel Implementation of a Chi-Squared-Made-to-Measure Algorithm for Modelling Observational Data
- Constraints on the Galactic Bar from the Hercules stream as traced with RAVE across the Galaxy
- Revisiting the Tale of Hercules: how stars orbiting the Lagrange points visit the Sun
- The Galactic Disc in Action Space as seen by Gaia DR2
- Radial Migration in Galactic Thick Discs
- Gas flow in barred potentials - III. Effects of varying the Quadrupole
- The effects of bar-spiral coupling on stellar kinematics in the Galaxy
- The signatures of the resonances of a large Galactic bar in local velocity space
- Extended distribution functions for our Galaxy
- Disassembling the Galaxy with angle-action coordinates
- Signatures of resonance and phase mixing in the Galactic disc
- On the ridges, undulations & streams in Gaia DR2: Linking the topography of phase-space to the orbital structure of an N-body bar
- The Pattern Speed of the OH/IR Stars in the Milky Way
- Gas dynamics in the Milky Way: a low pattern speed model
- The 4:1 Outer Lindblad Resonance of a long slow bar as a potential explanation for the Hercules stream
- The effect of bars and transient spirals on the vertical heating in disk galaxies
- Identifying resonances of the Galactic bar in Gaia DR2: I. Clues from action space
- Gas Dynamics in the Galaxy: Total Mass Distribution and the Bar Pattern Speed
- Characterising stellar halo populations I: An extended distribution function for halo K giants
- The Vertical Structure and Kinematics of Grand Design Spirals
- Gaia kinematics reveal a complex lopsided and twisted Galactic disc warp
- The vertical effects of disc non-axisymmetries from perturbation theory: the case of the Galactic bar
- The tilt of the velocity ellipsoid in the Milky Way disk
- A measurement of the Galactic plane mass density from binary pulsar accelerations
- Analysing surveys of our Galaxy -- II. Determining the potential
- Orbital tori for non-axisymmetric galaxies
- Towards a direct measure of the Galactic acceleration
- Bayes versus the virial theorem: inferring the potential of a galaxy from a kinematical snapshot
- Analysing surveys of our Galaxy I: basic astrometric data
- Bars and boxy/peanut bulges in thin and thick discs. II. Can bars form in hot thick discs?
- Constraining the Galactic potential via action-based distribution functions for mono-abundance stellar populations
- Milky Way Accelerometry via Millisecond Pulsar Timing
- Stellar Accelerations and the Galactic Gravitational Field
- Mapping the galactic gravitational potential with peculiar acceleration
- Eclipse timing the Milky Way's gravitational potential
- Probing Dark Matter Using Precision Measurements of Stellar Accelerations
- Revisiting the Stellar Velocity Ellipsoid - Hubble type relation: observations versus simulations
- Action-based Dynamical Modelling for the Milky Way Disk
- M2M modelling of the Galactic disc via PRIMAL: Fitting to Gaia Error Added Data
- Age dissection of the vertical breathing motions in Gaia DR2: evidence for spiral driving
- Angle-action variables for orbits trapped at a Lindblad resonance
- Charting Galactic Accelerations: When and How to Extract a Unique Potential from the Distribution Function
- Action-based Dynamical Modeling for the Milky Way Disk: The Influence of Spiral Arms
- Exploring the GalMer database: bar properties and non-circular motions
- The pattern speeds of vertical breathing waves