Kinematic modelling of the Milky Way using the RAVE and GCS stellar surveys

Abstract

We investigate the kinematic parameters of the Milky Way disc using the RAVE and GCS stellar surveys. We do this by fitting a kinematic model to the data taking the selection function of the data into account. For stars in the GCS we use all phase-space coordinates, but for RAVE stars we use only $(l,b,v_{\mathrm{los}})$. Using MCMC technique, we investigate the full posterior distributions of the parameters given the data. We investigate the `age-velocity dispersion' relation for the three kinematic components (${\sigma }_R,{\sigma }_{\varphi },{\sigma }_z$), the radial dependence of the velocity dispersions, the Solar peculiar motion ($U_{\odot },V_{\odot },W_{\odot }$), the circular speed ${\Theta }_0$ at the Sun and the fall of mean azimuthal motion with height above the mid-plane. We confirm that the Besançon-style Gaussian model accurately fits the GCS data, but fails to match the details of the more spatially extended RAVE survey. In particular, the Shu distribution function (DF) handles non-circular orbits more accurately and provides a better fit to the kinematic data. The Gaussian distribution function not only fits the data poorly but systematically underestimates the fall of velocity dispersion with radius. We find that correlations exist between a number of parameters, which highlights the importance of doing joint fits. The large size of the RAVE survey, allows us to get precise values for most parameters. However, large systematic uncertainties remain, especially in $V_{\odot }$ and ${\Theta }_0$. We find that, for an extended sample of stars, ${\Theta }_0$ is underestimated by as much as $10\%$ if the vertical dependence of the mean azimuthal motion is neglected. Using a simple model for vertical dependence of kinematics, we find that it is possible to match the Sgr A* proper motion without any need for $V_{\odot }$ being larger than that estimated locally by surveys like GCS.

27 pages, 13 figures, accepted for publication in ApJ

References in corpus (11)

• The Radial Velocity Experiment (RAVE): first data release
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The Milky Way's circular velocity curve between 4 and 14 kpc from APOGEE data
• The Geneva-Copenhagen Survey of the Solar neighbourhood II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk
• The Radial Velocity Experiment (RAVE): second data release
• PPM-Extended (PPMX) - a catalogue of positions and proper motions
• Cold Dark Matter Substructure and Galactic Disks II: Dynamical Effects of Hierarchical Satellite Accretion
• Re-visiting the relations: Galactic thin disc age-velocity dispersion relation
• Estimation of the Tilt of the Stellar Velocity Ellipsoid from RAVE and Implications for Mass Models

Cited by in corpus (50)

• The mass distribution and gravitational potential of the Milky Way
• The GALAH Survey: Scientific Motivation
• The GALAH+ Survey: Third Data Release
• Dynamical modelling of the Galactic bulge and bar: the Milky Way's bar pattern speed, stellar, and dark matter mass distribution
• Markov Chain Monte Carlo Methods for Bayesian Data Analysis in Astronomy
• The GALAH Survey: Observational Overview and Gaia DR1 companion
• The Rich Are Different: Evidence from the RAVE Survey for Stellar Radial Migration
• The power spectrum of the Milky Way: Velocity fluctuations in the Galactic disk
• Effects of Gas on Formation and Evolution of Stellar Bars and Nuclear Rings in Disk Galaxies
• Determination of the Local Standard of Rest using the LSS-GAC DR1
• Kinematics of the local disk from the RAVE survey and the Gaia first data release
• Uncertainties in the Galactic dark matter distribution: an update
• Recent advances in the determination of some Galactic constants in the Milky Way
• Planets Across Space and Time (PAST). I. Characterizing the Memberships of Galactic Components and Stellar Ages: Revisiting the Kinematic Methods and Applying to Planet Host Stars
• A Parametric Galactic Model toward the Galactic Bulge Based on Gaia and Microlensing Data
• The Fornax3D project: Assembly histories of lenticular galaxies from a combined dynamical and population orbital analysis
• The non-monotonic, strong metallicity dependence of the wide-binary fraction
• The SAMI Galaxy Survey: Mass and Environment as Independent Drivers of Galaxy Dynamics
• A self-consistent dynamical model of the Milky Way disc adjusted to Gaia data
• Does the stellar distribution flare? A comparison of stellar scale heights with LAB HI data
• Vertical Phase Mixing across the Galactic Disk
• Deciphering the evolution of the Milky Way discs: Gaia APOGEE Kepler giant stars and the Besançon Galaxy Model
• The stellar kinematics of co-rotating spiral arms in Gaia mock observations
• A transiting brown dwarf in a 2 hour orbit
• Effects of the selection function on metallicity trends in spectroscopic surveys of the Milky Way
• Clustering of Local Group distances: publication bias or correlated measurements? V. Galactic rotation constants
• The velocity ellipsoid in the Galactic disc using Gaia DR1
• Very wide companion fraction from Gaia DR2: a weak or no enhancement for hot jupiter hosts, and a strong enhancement for contact binaries
• Galactic googly: the rotation-metallicity bias in the inner stellar halo of the Milky Way
• The AMBRE Project: Solar neighbourhood chemodynamical constraints on Galactic disc evolution
• The imprints of the Galactic bar on the thick disk with RAVE
• Evidence of non-luminous matter in the center of M62
• Effects of the Central Mass Concentration on Bar Formation in Disk Galaxies
• Orbits of globular clusters computed with dynamical friction in the Galactic anisotropic velocity dispersion field
• Can ultralight dark matter explain the age-velocity dispersion relation of the Milky Way disc: A revised and improved treatment
• The Galactic Underworld: The spatial distribution of compact remnants
• Estimating Masses of Supermassive Black Holes in Active Galactic Nuclei from the Halpha Emission Line
• Imprints of Zero-Age Velocity Dispersions and Dynamical Heating on the Age-Velocity dispersion Relation
• Efficient radial migration by giant molecular clouds in the first several hundred Myr after the stellar birth
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• Stellar population synthesis based modelling of the Milky Way using asteroseismology of dwarfs and subgiants from Kepler
• The origin of ultramassive white dwarfs: hints from Gaia EDR3
• Chemodynamical Ages of Small-Scale Kinematic Structures of the Galactic Disc in the Solar Neighborhood from ~250,000 K and M Dwarfs
• Fundamental limits to orbit reconstruction due to non-conservation of stellar actions in a Milky Way-like simulation
• The K2 Galactic Archaeology Program: Overview, target selection and survey properties
• Signatures of the Galactic bar in high-order moments of proper motions measured by Gaia
• SDSS-IV MaNGA: Stellar rotational support in disk galaxies vs. central surface density and stellar population age
• Accurate orbital solution for the new and metal poor eclipsing binary Tycho~5227-1023-1
• Illuminating Hidden Pulsars: Scintillation-Enhanced Discovery of Two Binary Millisecond Pulsars in M13 with FAST
• A 'Quick Look' at All-Sky Galactic Archeology with TESS: 158,000 Oscillating Red Giants from the MIT Quick-Look Pipeline