Radial mixing in galactic discs

By J. Sellwood, J. Binney. 2002

763 citations recorded by the source corpus.

We show that spiral waves in galaxy discs churn the stars and gas in a manner that largely preserves the overall angular momentum distribution and leads to little increase in random motion. Changes in the angular momenta of individual stars are typically as large as ∼50 per cent over the lifetime of the disc. The changes are concentrated around the corotation radius for an individual spiral wave, but since transient waves with a wide range of pattern speeds develop in rapid succession, the entire disc is affected. This behaviour has profound consequences for the metallicity gradients with radius in both stars and gas, since the interstellar medium is also stirred by the same mechanism. We find observational support for stirring, propose a simple model for the distribution of stars over metallicity and age, and discuss other possible consequences.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “While it is widely accepted now that radial migration is responsible for the scatter in [Fe/H] at the same age (Sellwood & Binney 2002; Roškar et al. 2008; Schönrich & Binney 2009a), it has only recently been suggested that stars migrating from different radii present well-defined AMRs but…”
Metallicity distributions of mono-age stellar populations of the Galactic disc from the LAMOST Galactic spectroscopic surveys (2018, background): “…Toyouchi & Chiba 2018; Grisoni, Spitoni & Matteucci 2018), the supernova feedback (Kobayashi & Nakasato 2011), the secular evolution (e.g. radial migration; Sellwood & Binney 2002; Roškar et al. 2008; Schönrich & Binney 2009; Loebman et al. 2011; Haywood et al. 2016), the non-axisymmetric…”
OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO (2013, background): “In this context, it is relevant to mention the importance of radial migration for the formation of galactic disks (e.g., Sellwood & Binney 2002).”
The bifurcated age–metallicity relation of Milky Way globular clusters and its implications for the accretion history of the galaxy (2013, background): “This is likely because of the well known impact of radial migration (Sellwood & Binney 2002; Roškar et al. 2008) in scattering the disk AMR to higher metallicities at a given age — as well as the fact that we are considering clusters from the entire disk and some may be more closely linked to a…”
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) (2007, neutral): “…stellar populations, which, in turn, fuel ever more sophisticated galactic dynamical and chemodynamical models (e.g., Chiappini et al. 2001, 2003; Sellwood & Binney 2002; Abadi et al. 2003; Bournaud et al. 2009; Schönrich & Binney 2009; Minchev & Famaey 2010; Bird et al. 2013; Minchev et al.…”
A characteristic oxygen abundance gradient in galaxy disks unveiled with CALIFA (2013, background): “…Koeppen 1992; Portinari & Chiosi 2000; Schönrich & Binney 2009; Spitoni & Matteucci 2011), resonance scattering with transient spiral density waves (Sellwood & Binney 2002), and the overlap of spiral and bar resonances (Minchev et al. 2011); (ii) minor mergers and captures of or perturbations by…”
THE EFFECT OF RADIAL MIGRATION ON GALACTIC DISKS (2014, methodology): “…work has relied on direct numerical simulation, some studies are based on the response of equilibrium disk models to transient spiral modes (Sellwood & Binney 2002; Grand et al. 2012; Solway et al. 2012; Sellwood & Carlberg 2014) or to the tidal perturbation of a massive satellite…”
Stellar population gradients in galaxy discs from the CALIFA survey - The influence of bars (2014, background): “…stars in galactic discs may migrate radially across significant distances has received a lot of attention in the literature over the past few years (Sellwood & Binney 2002; Roškar et al. 2008a,b; Berentzen et al. 2007; Minchev & Famaey 2010; Minchev et al. 2011, 2012a,b, 2014a,b; Grand et al.…”
Misaligned angular momentum in hydrodynamic cosmological simulations: warps, outer discs and thick discs (2010, background): “Radial migration results from the interaction of star particles with transient spiral arms, formed through gravitational instabilities (Sellwood & Binney 2002).”
New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey (2011, background): “A natural explanation is provided by the radial migration of stars (Sellwood & Binney 2002).”
Constraining the thick disc formation scenario of the Milky Way (2014, neutral): “The importance of migrations has been shown by Sellwood & Binney (2002) and has been studied in different N-body simulations (Roškar et al. (2012); Minchev et al. (2011); Di Matteo et al. (2011); Bird et al. (2012) among others).”
Isochrone ages for field dwarfs: method and application to the age–metallicity relation (2004, background): “An alternative explanation for a high intrinsic dispersion was explored by Sellwood & Binney (2002) and Lépine, Acharova & Mishurov (2003), who showed that radial migration of the stellar orbits without conservation of the angular momentum, for instance under the influence of spiral arm…”
Impacts of a flaring star-forming disc and stellar radial mixing on the vertical metallicity gradient (2016, background): “On the other hand, co-rotation radial migration indicates gain or loss of angular momentum of stars at the corotation resonance of the bar or spiral arms, which does not involve any kinematic heating (Sellwood & Binney 2002).”
BREATHING FIRE: HOW STELLAR FEEDBACK DRIVES RADIAL MIGRATION, RAPID SIZE FLUCTUATIONS, AND POPULATION GRADIENTS IN LOW-MASS GALAXIES (2015, background): “…to cause radial migration in massive disk galaxies, where stellar orbits are scattered via interactions with massive non-axisymmetric structures (for example, Wielen 1977; Binney & Lacey 1988), or are stirred by spiral waves and/or bars (for example, Sellwood & Binney 2002; Minchev et al. 2011).”
The GALAH survey: scientific motivation (2015, background): “It is believed to be driven by the torques of the Galactic bar and transient spiral arms, which can move stars radially inwards and outwards from one near-circular orbit to another (Sellwood & Binney 2002; Minchev & Famaey 2010), without significantly heating the disc.”
Radial migration does little for Galactic disc thickening (2012, background): “Most recently, we (Minchev et al., 2012a) demonstrated that, in these same models, the strongest changes of angular momentum occur near the bar’s corotation (CR) region, in contradiction to the expectation that patterns need to be transient for efficient migration (Sellwood and Binney, 2002).”
INSIDE OUT AND UPSIDE DOWN: TRACING THE ASSEMBLY OF A SIMULATED DISK GALAXY USING MONO-AGE STELLAR POPULATIONS (2013, background): “Radial migration of stars is also an important ingredient in understanding chemical evolutin (Wielen et al. 1996; Sellwood & Binney 2002; Roškar et al. 2008a; Schönrich & Binney 2009a), and it arises naturally in our simulation.”
Dawes Review 4: Spiral Structures in Disc Galaxies (2014, background): “The stars oscillate along the curve of circular motion by undergoing change in terms of both angular momentum and energy (Sellwood & Binney 2002; Grand et al. 2012a; Roškar et al. 2012; Baba et al. 2013).”
Astrophysics with Presolar Stardust (2004, background): “However, Sellwood & Binney (2002) have given support to the general idea by calculating radial migration of low-mass stars as a result of scattering from spiral density waves (rather than from molecular clouds).”