Chemodynamical evolution of the Milky Way disk II: Variations with Galactic radius and height above the disk plane

By I. Minchev, C. Chiappini, M. Martig. 2014

183 citations recorded by the source corpus.

the date of receipt and acceptance should be inserted later Abstract. In the first paper of this series (paper I) we presented a new approach for studying the chemodynamical evolution in disk galaxies, focusing on the Milky Way. While in paper I we studied extensively the Solarvicinity, here we extend these results to different distances from the Galactic center, looking for variations of observables that can be related to on-going and future spectroscopic surveys. By separating the effects of kinematic heating and radial migration, we show that migration is much more important, even for the oldest and hottest stellar population. The distributions of stellar birth guiding radii and final guiding radii (signifying contamination from migration and heating, respectively) widen with increasing distance from the Galactic center. As a result, the slope in the age-metallicity relation flattens significantly at Galactic radii larger than solar. We predict that the metallicity distributions of (unbiased) samples at different distances from the Galactic center peak at approximately the same value, (Fe/H) ≈− 0.15 dex, and have similar metal-poor tails extending to (Fe/H) ≈− 1.3 dex. In contrast, the metal-rich tail decreases with increasing radius, thus giving rise to the expected decline of mean metallicity with radius. Similarly, the (Mg/Fe) distribution always peaks at ≈ 0.15 dex, but its low-end tail is lost as radius increases, while the high-end diminishes at (Mg/Fe) ≈ 0.45 dex. The radial metallicity and (Mg/Fe) gradients in our model show significant variations with height above the plane because of changes in the mixture of stellar ages. An inversion in the radial metallicity gradient is found from negative to weakly positive (at r < 10 kpc), and from positive to negative for the (Mg/Fe) gradient, with increasing distance from the disk plane. We relate this to the combined effect of (i) the predominance of young stars close to the disk plane and old stars away from it, (ii) the more concentrated older stellar component, and (iii) the flaring of mono-age disk populations. We also investigate the effect of recycled gas flows on the mean (Fe/H) and find that in the region 4 < r < 12 kpc the introduced errors are less than 0.05-0.1 dex, related to the fact that inward and outward flows mostly cancel in that radial range. We show that radial migration cannot compete with the inside-out formation of the disk, exposed by the more centrally concentrated older disk populations, and consistent with recent observations.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/91b282f6a2cb201cd5d57bc9553746013b62a2a3

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Citations in the corpus

The Lives of Stars: Insights from the TGAS–RAVE–LAMOST Data Set (2018, background): “…in the context of cosmological galaxy evolution with effects such as insideout formation scenarios (Pilkington et al. 2012), migration (Kubryk et al. 2015, Kubryk et al. 2015, Minchev et al. 2014), spiral arm influence (Grand et al. 2016), and realistic galactic environments (Ma et al. 2016).”
The age–metallicity structure of the Milky Way disc using APOGEE (2017, background): “However, these results may be reconciled by invoking a more active accretion history in the early life of the disk, which could have suppressed flaring (e.g. Minchev et al. 2014b).”
PLATO as it is: a legacy mission for Galactic archaeology (2017, unknown): “The framework for chemodynamical models tailored to the Milky Way now exists (e.g., Minchev et al. 2014), as well as tools to best compare model predictions to the data (e.g., Anders et al. 2016; Sharma et al. 2011).”
Impacts of a flaring star-forming disc and stellar radial mixing on the vertical metallicity gradient (2016, background): “…distributions of (unbiased) samples at different distances from the Galctic centre peak at approximately the same value, [Fe/H]∼ −0.15 dex” (Minchev et al. 2014), which is inconsistent with the recent results of the SDSS/Apache Point Observatory Galactic Evolution Experiment (APOGEE)…”
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data (2017, background): “…be explained by the radial metallicity gradient at formation time being flatter at earlier epochs or radial mixing flattening the radial metallicity gradient for the older stars (e.g. Roškar et al. 2008; Sánchez-Blázquez et al. 2009; Minchev et al. 2014; Grand et al. 2015; Kawata et al. 2017).”
Chemodynamical evolution of the Milky Way disk - I. The solar vicinity (2012, methodology): “3 Minchev et al. (2012c) showed that migrators contract (vertically cool) the disk inside the bar’s CR, further contributing to disk flaring.”
Chemodynamics of the Milky Way - I. The first year of APOGEE data (2013, result): “This is also in good agreement with the recent predictions of the chemodynamical model of Minchev et al. (2013, 2014) (but see below).”
Estimating stellar birth radii and the time evolution of Milky Way’s ISM metallicity gradient (2018, methodology): “Minchev et al. (2014b) found a decline in the stellar velocity dispersion as a function of [Mg/Fe] in data from the RAVE (Steinmetz et al. 2006) and SEGUE (Yanny et al. 2009) surveys (seen also in Gaia-ESO data by Guiglion et al. 2015; Hayden et al. 2018), reasoning that these high-[α/Fe],…”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, background): “N-body and hydrodynamic simulations are becoming increasingly useful to help understand both formation and evolutionary processes (Stinson et al. 2013, Minchev et al. 2014, Scannapieco et al. 2015, Feng et al. 2016).”
CHEMICAL CARTOGRAPHY WITH APOGEE: METALLICITY DISTRIBUTION FUNCTIONS AND THE CHEMICAL STRUCTURE OF THE MILKY WAY DISK (2015, methodology): “We find that the MDFs from the simulations closely match the APOGEE observations of the MDF in the solar neighborhood and the uniformity of the MDF above the plane (see Figure 9 of Minchev et al. 2014).”
THE RELATIONSHIP BETWEEN MONO-ABUNDANCE AND MONO-AGE STELLAR POPULATIONS IN THE MILKY WAY DISK (2016, methodology): “A.1 by MCM14.”
THE STELLAR POPULATION STRUCTURE OF THE GALACTIC DISK (2015, background): “…value, this finding implies that little radial migration has occurred in the high-[α/Fe] populations, because effects such as those from mergers that can undo the flaring by mixing in-situ and migrated populations (Minchev et al. 2014) do not apply to the mono-abundance populations considered here.”
Vertical disc heating in Milky Way-sized galaxies in a cosmological context (2015, background): “…of the radially migrated stars in N-body simulations of isolated discs and found that overall radial migration does not have a significant effect on galactic disc thickness, and may even cool the outer parts of the disc in the regime of strong satellite interaction (Minchev et al. 2013, 2014a).”