The effects of bar-spiral coupling on stellar kinematics in the Galaxy

Abstract

We investigate models of the Milky Way disc taking into account simultaneously the bar and a two-armed quasi-static spiral pattern. Away from major resonance overlaps, the mean stellar radial motions in the plane are essentially a linear superposition of the isolated effects of the bar and spirals. Thus, provided the bar is strong enough, even in the presence of spiral arms, these mean radial motions are predominantly affected by the Galactic bar for large scale velocity fluctuations. This is evident when comparing the peculiar line-of-sight velocity power spectrum of our coupled models with bar-only models. However, we show how forthcoming spectroscopic surveys could disentangle bar-only non-axisymmetric models of the Galaxy from models in which spiral arms have a significant amplitude. We also point out that overlaps of low-order resonances are sufficient to enhance stellar churning within the disc, even when the spirals amplitude is kept constant. Nevertheless, for churning to be truly non-local, stronger or (more likely) transient amplitudes would be needed: otherwise the disc is actually mostly unaffected by churning in the present models. Finally, regarding vertical breathing modes, the combined effect of the bar and spirals on vertical motions is a clear non-linear superposition of the isolated effects of both components, significantly superseding the linear superposition of modes produced by each perturber separately, thereby providing an additional effect to consider when analysing the observed breathing mode of the Galactic disc in the extended Solar neighbourhood.

13 pages, 12 figures. MNRAS. Accepted for publication. v2 is the published version

References in corpus (16)

• The Structure of the Milky Way's Bar Outside the Bulge
• Vertical disc heating in Milky Way-sized galaxies in a cosmological context
• Made-to-Measure models of the Galactic Box/Peanut bulge: stellar and total mass in the bulge region
• When the Milky Way turned off the lights: APOGEE provides evidence of star formation quenching in our Galaxy
• The formation of spiral arms and rings in barred galaxies
• Transient spirals as superposed instabilities
• Radial and vertical flows induced by galactic spiral arms: likely contributors to our "wobbly Galaxy''
• Modelling the Galactic disc: perturbed distribution functions in the presence of spiral arms
• The power spectrum of the Milky Way: Velocity fluctuations in the Galactic disk
• Quantifying stellar radial migration in an N-body simulation: blurring, churning, and the outer regions of galaxy discs
• Resonances in Barred Galaxies
• Gas and Stellar Motions and Observational Signatures of Co-Rotating Spiral Arms
• The Vertical Structure and Kinematics of Grand Design Spirals
• The vertical effects of disc non-axisymmetries from perturbation theory: the case of the Galactic bar
• The stellar kinematics of co-rotating spiral arms in Gaia mock observations
• Kinematics of symmetric Galactic longitudes to probe the spiral arms of the Milky Way with Gaia

Cited by in corpus (79)

• Gaia Data Release 2: Mapping the Milky Way disc kinematics
• The Influence of Sagittarius and the Large Magellanic Cloud on the Milky Way Galaxy
• Dark matter local density determination: recent observations and future prospects
• Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way
• Origin of chemically distinct discs in the Auriga cosmological simulations
• Radial Distribution of Stellar Motions in Gaia DR2
• Transient spiral structure and the disc velocity substructure in Gaia DR2
• Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry
• The Canada-France Imaging Survey: First results from the u-band component
• On the ridges, undulations & streams in Gaia DR2: Linking the topography of phase-space to the orbital structure of an N-body bar
• Effects of baryonic and dark matter substructure on the Pal 5 stream
• The 4:1 Outer Lindblad Resonance of a long slow bar as a potential explanation for the Hercules stream
• Phylogeny of the Milky Way's inner disk and bulge populations: Implications for gas accretion, (the lack of) inside-out thick disk formation, and quenching
• Identifying resonances of the Galactic bar in Gaia DR2: I. Clues from action space
• Broken into Pieces: ATLAS and Aliqa Uma as One Single Stream
• Bimodality of [α/Fe]-[Fe/H] distributions is a natural outcome of dissipative collapse and disc growth in Milky Way-type galaxies
• Lessons from the Auriga discs: The hunt for the Milky Way's ex-situ disc is not yet over
• Bending Waves in the Milky Way's disc from halo substructure
• Measuring the local dark matter density with LAMOST DR5 and Gaia DR2
• Kinematics with Gaia DR2: The Force of a Dwarf
• Stellar halo substructure generated by bar resonances
• Staying away from the bar: the local dynamical signature of slow and fast bars in the Milky Way
• Chemo-kinematics of the Milky Way spiral arms and bar resonances: connection to ridges and moving groups in the Solar vicinity
• Gaia DR1 evidence of disrupting Perseus Arm
• The COMBS Survey -- II. Distinguishing the Metal-Poor Bulge from the Halo Interlopers
• Kinematics and dynamics of Gaia red clump stars
• Implications of a time-varying Galactic potential for determinations of the dynamical surface density
• Spontaneous generation of bending waves in isolated Milky Way-like discs
• Dissecting the Phase Space Snail Shell
• Identifying resonances of the Galactic bar in Gaia DR2: II. Clues from angle space
• Did Sgr cause the vertical waves in the solar neighbourhood?
• An ever-present $Gaia$ snail shell triggered by a dark matter wake
• Dynamical model of the Milky Way using APOGEE and Gaia data
• The Pristine Inner Galaxy Survey (PIGS) V: a chemo-dynamical investigation of the early assembly of the Milky Way with the most metal-poor stars in the bulge
• Vertical Phase Mixing across the Galactic Disk
• Distribution functions for resonantly trapped orbits in the Galactic disc
• A Dynamical Model for Clustered Star Formation in the Galactic Disk
• Migration and kinematics in growing disc galaxies with thin and thick discs
• The kinematic signature of the Galactic warp in Gaia DR1 - I. The Hipparcos subsample
• Mapping Milky Way disk perturbations in stellar number density and vertical velocity using Gaia DR3
• Young stars as tracers of a barred-spiral Milky Way
• Gaia DR3 features of the phase spiral and its possible relation to internal perturbations
• Chemodynamical signatures of bar resonances in the Galactic disk: current data and future prospects
• The Great Wave: Evidence of a large-scale vertical corrugation propagating outwards in the Galactic disc
• Kinematic footprint of the Milky Way spiral arms in Gaia EDR3
• New insights in the origin and evolution of the old, metal-rich open cluster NGC 6791
• A Kpc Scale Molecular Wave in the Inner Galaxy: Feather of the Milky Way?
• On the relevance of chaos for halo stars in the solar neighbourhood II
• A Map of the Local Velocity Substructure in the Milky Way Disk
• The North/South Asymmetry of the Galaxy: Possible Connection to the Vertical Phase Space Snail
• Stars with fast Galactic rotation observed in Gaia TGAS: a signature driven by the Perseus arm?
• High-speed stars. II. An unbound star, young stars, bulge metal-poor stars, and Aurora candidates
• Ripples spreading across the Galactic disc. Interplay of direct and indirect effects of the Sagittarius dwarf impact
• How the bar properties affect the induced spiral structure
• Growing Local arm inferred by the breathing motion
• Asymmetric metallicity patterns in the stellar velocity space with RAVE
• Stellar escapers from M67 can reach solar-like Galactic orbits
• Radial Wave in the Galactic Disk: New Clues to Discriminate Different Perturbations
• Could very low-metallicity stars with rotation-dominated orbits have been shepherded by the bar?
• Peeking beneath the precision floor -- II. Probing the chemo-dynamical histories of the potential globular cluster siblings, NGC 288 and NGC 362
• A non-axisymmetric potential for the Milky Way disk
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data I. Method validation
• Accelerated phase-mixing in the stellar halo due to a rotating bar
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data II. Chrono-chemo-kinematics of the disc
• The Ophiuchus stream progenitor: a new type of globular cluster and its possible Sagittarius connection
• Quantifying the influence of bars on action-based dynamical modelling of disc galaxies
• Effects of secular growth and mergers on the evolution of metallicity gradients and azimuthal variations in a Milky Way-like galaxy
• Dynamical streams in the local stellar halo
• Exploring the centre of mass properties of LG-like galaxies
• Fundamental limits to orbit reconstruction due to non-conservation of stellar actions in a Milky Way-like simulation
• Collisionless Boltzmann equation approach for the study of stellar discs within barred galaxies
• Dark matter spiral arms in Milky Way-like halos
• The first r-process enhanced star confirmed to be a member of the Galactic bulge
• Mass-velocity dispersion relation by using the \textit{Gaia} data and its effect on interpreting short-duration and degenerate microlensing events
• Optimal Emergency Frequency Control Based on Coordinated Droop in Multi-Infeed Hybrid AC-DC System
• The large-scale kinematics of young stars in the Milky Way disc: first results from SDSS-V
• Smart: A program to automatically compute accelerations and variational equations
• The COMBS Survey -- III. The Chemodynamical Origins of Metal-Poor Bulge Stars
• Galactic tides in the Solar System within a non-axisymmetric Milky Way model adjusted to Gaia data