The Non-Axisymmetric Influence: Radius and Angle-Dependent Trends in a Barred Galaxy

Abstract

Many disc galaxies host galactic bars, which exert time-dependent, non-axisymmetric forces that can alter the orbits of stars. There should be both angle and radius-dependence in the resulting radial rearrangement of stars ('radial mixing') due to a bar; we present here novel results and trends through analysis of the joint impact of these factors. We use an N-body simulation to investigate the changes in the radial locations of star particles in a disc after a bar forms by quantifying the change in orbital radii in a series of annuli at different times post bar-formation. We find that the bar induces both azimuth angle- and radius- dependent trends in the median distance that stars have travelled to enter a given annulus. Angle-dependent trends are present at all radii we consider, and the radius-dependent trends roughly divide the disc into three 'zones'. In the inner zone, stars generally originated at larger radii and their orbits evolved inwards. Stars in the outer zone likely originated at smaller radii and their orbits evolved outwards. In the intermediate zone, there is no net inwards or outwards evolution of orbits. We adopt a simple toy model of a radius-dependent initial metallicity gradient and discuss recent observational evidence for angle-dependent stellar metallicity variations in the Milky Way in the context of this model. We briefly comment on the possibility of using observed angle-dependent metallicity trends to learn about the initial metallicity gradient(s) and the radial rearrangement that occurred in the disc.

arXiv commentPublished in MNRAS, updated to match final refereed version in which a discussion on external galaxies was added

References in corpus (59)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• A Universal Density Profile from Hierarchical Clustering
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
• Co-formation of the Galactic disc and the stellar halo
• Chemical evolution with radial mixing
• Extragalactic Science, Cosmology and Galactic Archaeology with the Subaru Prime Focus Spectrograph (PFS)
• Morphology, photometry and kinematics of N-body bars. I Three models with different halo central concentrations
• The Structure of the Milky Way's Bar Outside the Bulge
• Life in the fast lane: a direct view of the dynamics, formation, and evolution of the Milky Way's bar
• On the fine structure of the Cepheid metallicity gradient in the Galactic thin disk
• Estimating stellar birth radii and the time evolution of the Milky Way's ISM metallicity gradient
• Star formation history of barred disc galaxies
• Mapping metallicity variations across nearby galaxy disks
• Measuring Radial Orbit Migration in the Milky Way Disk
• Signatures of radial migration in barred galaxies: Azimuthal variations in the metallicity distribution of old stars
• Red giants observed by CoRoT and APOGEE: The evolution of the Milky Way's radial metallicity gradient
• Gaia Data Release 3: Mapping the asymmetric disc of the Milky Way
• The effect of radial migration on galactic disks
• The Milky Way bar and bulge revealed by APOGEE DR16 and Gaia EDR3
• Radial Migration in Galactic Thick Discs
• Spiral-induced velocity and metallicity patterns in a cosmological zoom simulation of a Milky Way-sized galaxy
• Unravelling the mystery of the M31 bar
• Understanding inverse metallicity gradients in galactic discs as a consequence of inside-out formation
• Stellar diffusion in barred spiral galaxies
• The disc origin of the Milky Way bulge: Dissecting the chemo-morphological relations using N-body simulations and APOGEE
• The Chemical Evolution Carousel of Spiral Galaxies: Azimuthal Variations of Oxygen Abundance in NGC1365
• Chemical abundance patterns in the inner Galaxy: the Scutum Red Supergiant Clusters
• An adaptive algorithm for n-body field expansions
• Evidence of ongoing radial migration in NGC 6754: Azimuthal variations of the gas properties
• Gaia Data Release 3: Chemical cartography of the Milky Way
• DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor
• Anomalously low metallicity regions in MaNGA star-forming galaxies: Accretion Caught in Action?
• Stellar Abundance Maps of the Milky Way Disk
• Constraining churning and blurring in the Milky Way using large spectroscopic surveys -- an exploratory study
• Trojans in the Solar Neighborhood
• Panchromatic Hubble Andromeda Treasury XII. Mapping Stellar Metallicity Distributions in M31
• SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies
• Stellar populations across galaxy bars in the MUSE TIMER project
• The chemical signature of the Galactic spiral arms revealed by Gaia DR3
• Stellar metallicity variations across spiral arms in disk galaxies with multiple populations
• Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration
• The stellar populations of the central region of M31
• What determines the flatness of X-shaped structures in edge-on galaxies
• The BaLROG project - II. Quantifying the influence of bars on the stellar populations of nearby galaxies
• Migration and Mixing in the Galactic Disc from Encounters between Sagittarius and the Milky Way
• EXP: N-body integration using basis function expansions
• Using Torque to Understand Barred Galaxy Models
• Bars and boxy/peanut bulges in thin and thick discs. II. Can bars form in hot thick discs?
• Reliability and limitations of inferring birth radii in the Milky Way disk
• Using Commensurabilities and Orbit Structure to Understand Barred Galaxy Evolution
• The imprint of radial migration on the vertical structure of galaxy disks
• The chemistry of stars in the bar of the Milky Way
• Chemodynamical signatures of bar resonances in the Galactic disk: current data and future prospects
• 4MOST Consortium Survey 3: Milky Way Disc and Bulge Low-Resolution Survey (4MIDABLE-LR)
• The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge
• Photometric Signature of Ultra-Harmonic Resonances in Barred Galaxies
• Unravelling stellar populations in the Andromeda Galaxy

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• Constraints on the history of Galactic spiral arms revealed by Gaia GSP-Spec alpha-elements
• Rediscovering the Milky Way with orbit superposition approach and APOGEE data II. Chrono-chemo-kinematics of the disc
• Metal-rich stellar counterpart of the Radcliffe Wave and the 3D chemical footprints of the Milky Way spiral arms
• The Impact of Bars, Spirals and Bulge-Size on Gas-Phase Metallicity Gradients in MaNGA Galaxies
• Massive Star Clusters in the Semi-Analytical Galaxy Formation Model L-Galaxies 2020