Origin and structure of the Galactic disc(s)

By R. Schoenrich, J. Binney. 2009

266 citations recorded by the source corpus.

We examine the chemical and dynamical structure in the solar neighbourhood of a model Galaxy that is the endpoint of a simulation of the chemical evolution of the Milky Way in the presence of radial mixing of stars and gas. Although the simulation's star formation rate declines monotonically from its unique peak and no merger or tidal event ever takes place, the model replicates all known properties of a thick disc, as well as matching special features of the local stellar population such as a metal-poor extension of the thin disc that has high rotational velocity. We divide the disc by chemistry and relate this dissection to observationally more convenient kinematic selection criteria. We conclude that the observed chemistry of the Galactic disc does not provide convincing evidence for a violent origin of the thick disc, as has been widely claimed.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “Schönrich & Binney (2009a) argued that the presence of a negative correlation in the MVR for stars in the chem- ically defined thin disc (or more correctly, the low-[α/Fe] sequence) is an indication of migration.”
The Gaia-ESO Survey : radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk (2014, methodology): “For example, the semi-analytical model by (Schönrich & Binney 2009b, see their Fig.”
Measuring the vertical age structure of the Galactic disc using asteroseismology and SAGA (2015, background): “In particular, it is unclear if the thin and thick disc in the Milky Way are real, separated structural entities or not (e.g. Norris 1987; Nemec & Nemec 1991; Schönrich & Binney 2009b; Bovy, Rix & Hogg 2012).”
Idealized models for galactic disc formation and evolution in ‘realistic’ ΛCDM haloes (2012, background): “It has been argued that the ages of thin disc stars are consistent with formation after z ∼ 1.5 (e.g. Reddy, Lambert & Allende Prieto 2006), but it is not clear, if a two-component division of the Milky Way disc into thin and thick components is sensible (e.g. Schönrich & Binney 2009).”
The effects of radial migration on the vertical structure of Galactic discs (2012, methodology): “Their conclusion disagrees sharply with the findings of Schönrich & Binney (2009b), who assumedenergy conservation rather than action conservation when modeling the vertical distribution in their analytic models.”
THE VERTICAL METALLICITY GRADIENT OF THE MILKY WAY DISK: TRANSITIONS IN [α/Fe] POPULATIONS (2014, methodology): “Finally, work by Roškar et al. (2008), Schönrich & Binney (2009a), and Loebman et al. (2011) propose that the thick disk forms via radial migration, whether by processes internal to the galaxy or enhanced by mergers or close encounters (Quillen et al. 2009; Bird et al. 2012).”
Through thick and thin: kinematic and chemical components in the solar neighbourhood (2010, methodology): “Using a simple but plausible model that includes radial migration, Schönrich & Binney (2009b) demonstrate that most available data for the thin and thick disks can be accommodated without invoking a violent accretion event at all.”
Constraining the Milky Way assembly history with Galactic Archaeology (2016, methodology): “…models tuned to fit the local metallicity distribution, velocity dispersion, and chemical gradients, etc., today (e.g., Kubryk et al. 2015; Schönrich & Binney 2009a) or Extended distribution functions (Sanders & Binney, 2015): − Easy to vary parameters − Provide good description of the…”
The Milky Way’s stellar disk (2013, background): “…infall (e.g., Quinn et al. 1993); outward radial migration appears to conserve approximately the vertical action (not the vertical energy, cf. Schönrich & Binney (2009)), which will slightly thicken the disk portions that have migrated outward and slightly decrease their vertical velocity…”
OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO (2013, methodology): “However, bottom-up models in which radial mixing is an important component of the process of Galactic disk formation have been shown to explain these data as successfully as the merger models, and in some cases even better (e.g., Schönrich & Binney 2009b; Loebman et al. 2011; Bird et al. 2012).”
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data (2017, background): “…fixed radius, radial mixing of stars could have brought more metal-rich stars from the inner region and more metal-poor stars from the outer region (e.g. Sellwood & Binney 2002; Schönrich & Binney 2009a,b; Minchev et al. 2013; Grand et al. 2015), and this would increase the metallicity dispersion.”
New constraints on the chemical evolution of the solar neighbourhood and galactic disc(s) - improved astrophysical parameters for the Geneva-Copenhagen Survey (2011, background): “…assembled from local stars, following a local age metallicity relation, but also from stars originating from the inner (more metal-rich) and outer (more metal-poor) Galactic disc that have migrated to the present position on different timescales (Roškar et al. 2008; Schönrich & Binney 2009a).”
FORMATION AND EVOLUTION OF THE DISK SYSTEM OF THE MILKY WAY: [α/Fe] RATIOS AND KINEMATICS OF THE SEGUE G-DWARF SAMPLE (2011, methodology): “…above have used methods of assigning individual stars to membership in the thin- and thick-disk populations (based on a given star’s location or kinematics) that introduce manifest biases that can confound interpretations (as previously noted by Schönrich & Binney 2009b and Loebman et al. 2010).”
Vertical disc heating in Milky Way-sized galaxies in a cosmological context (2015, background): “In this section, we investigate the effects of radial migration from bar and spiral structure on the vertical structure of the disc, which has been recently debated (e.g. Schönrich & Binney 2009; Minchev et al. 2012; Martig et al. 2014).”
The structure and dynamical evolution of the stellar disc of a simulated Milky Way-mass galaxy (2016, background): “…& Quillen 2006; Saha et al. 2010; Faure et al. 2014; Yurin & Springel 2015; Grand et al. 2016), (2) radial migration (e.g. Sellwood & Binney 2002; Schönrich & Binney 2009b; Loebman et al. 2011; however, see e.g. Minchev et al. 2012), (3) perturbation of satellites and sub-halos (e.g. Quinn et…”
Thin disc, thick disc and halo in a simulated galaxy (2012, background): “Schönrich & Binney (2009) attain bimodal distributions in [O/Fe] as a consequence of their assumptions about SFRs and metal enrichment, without a star formation hiatus (their star formation is assumed to exponentially decay).”
THE GENESIS OF THE MILKY WAY'S THICK DISK VIA STELLAR MIGRATION (2010, background): “On the other hand, in the model of Schönrich & Binney (2009), that same population shows considerable lag from the LSR.”
THE METALLICITY DISTRIBUTION FUNCTIONS OF SEGUE G AND K DWARFS: CONSTRAINTS FOR DISK CHEMICAL EVOLUTION AND FORMATION (2011, methodology): “We also calculate mass weights based on the Schönrich & Binney (2009a, 2009b) Galaxy models (SB), which utilize a Salpeter IMF (Salpeter 1955), to examine how much these values will vary with different assumptions about the mass function (Section 6.4.1).”
THE RELATIONSHIP BETWEEN MONO-ABUNDANCE AND MONO-AGE STELLAR POPULATIONS IN THE MILKY WAY DISK (2016, methodology): “Formation of thick disks by radial migration was proposed as a mechanism by Schönrich and Binney (2009), later on advocated by Loebman et al. (2011) and Roškar et al. (2013).”