Modelling the chemical evolution of the Milky Way

Matteucci, Francesca

doi:10.48550/arxiv.2106.13145

Cited by 3 publications

(5 citation statements)

References 264 publications

(421 reference statements)

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“…Regardless of age, this hints at a very small difference in the initial mass distribution of stars in the inner and outer parts of the Galaxy (e.g. Griffith et al 2021b;Krumholz 2014;Matteucci 2021). Quantitative modeling, however, is needed to understand and explain the underlying parameters of the environment that give rise to the systematic changes in individual abundance distributions over time and radius at fixed (Fe, Mg) as seen in the distributions of the residuals of these elements (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Quantitative modeling, however, is needed to understand and explain the underlying parameters of the environment that give rise to the systematic changes in individual abundance distributions over time and radius at fixed (Fe, Mg) as seen in the distributions of the residuals of these elements (e.g. Johnson et al 2021;Spitoni et al 2021;Matteucci 2021;Philcox & Rybizki 2019;Rybizki et al 2017, and references therein).…”

Section: Discussionmentioning

confidence: 99%

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The homogeneity of the star forming environment of the Milky Way disk over time

Ness,

Wheeler,

McKinnon

et al. 2021

Preprint

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Stellar abundances and ages afford the means to link chemical enrichment to galactic formation. In the Milky Way, individual element abundances show tight correlations with age, which vary in slope across ([Fe/H]-[α/Fe]). Here, we step from characterising abundances as measures of age, to understanding how abundances trace properties of stellar birth-environment in the disk over time. Using measurements from ∼27,000 APOGEE stars (R=22,500, SNR>200), we build simple local linear models to predict a sample of elements (X = Si, O, Ca, Ti, Ni, Al, Mn, Cr) using (Fe, Mg) abundances alone, as fiducial tracers of supernovae production channels. Given [Fe/H] and [Mg/H], we predict these elements, [X/H], to about double the uncertainty of their measurements. The intrinsic dispersion, after subtracting measurement errors in quadrature is ≈ 0.015 − 0.04 dex. The residuals of the prediction (measurement − model) for each element demonstrate that each element has an individual link to birth properties at fixed (Fe, Mg). Residuals from primarily massive-star supernovae (i.e. Si, O, Al) partially correlate with guiding radius. Residuals from primarily supernovae Ia (i.e. Mn, Ni) partially correlate with age. A fraction of the intrinsic scatter that persists at fixed (Fe, Mg), however, after accounting for correlations, does not appear to further discriminate between birth properties that can be traced with present-day measurements. Presumably, this is because the residuals are also, in part, a measure of the typical (in)-homogeneity of the disk's stellar birth environments, previously inferred only using open-cluster systems. Our study implies at fixed birth radius and time, there is a median scatter of ≈ 0.01 − 0.015 dex in elements generated in supernovae sources.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

The homogeneity of the star forming environment of the Milky Way disk over time

Ness,

Wheeler,

McKinnon

et al. 2021

Preprint

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“…In order to tackle this, many previous works have sought to interpret the chemical abundance distribution of stellar populations in the Galaxy via the use of Galactic chemical evolution models. Beginning with the pioneering work by Tinsley (1980) 3 , there have been many papers that have attempted to decipher how the Milky Way disc has reached its current form and chemical compositions using a plethora of different chemical evolution models (e.g., Matteucci & Francois 1989;Rana 1991;Chiappini et al 1997;Travaglio et al 1999;Kobayashi et al 2006;Schönrich & Binney 2009;Minchev et al 2013;Pilkington et al 2012;Nomoto et al 2013;Kobayashi et al 2020a;Matteucci 2021).…”

Section: Our Results In the Context Of Galactic Chemical Evolution Mo...mentioning

confidence: 99%

“…The ensemble data that we examine are compared to the predictions of Galactic Chemical Evolution models (GCE), which describe the star formation and chemical enrichment of the interstellar medium in terms of a set of mass conservation equations. This technique has been adopted extensively (e.g., Tinsley 1980;Matteucci & Francois 1989;Prantzos et al 1993;Timmes et al 1995;Pagel 1997;Chiappini et al 1997;McWilliam 1997;Kobayashi et al 2000;Matteucci 2016; Kobayashi et al 2020b;Matteucci 2021). It has also led to the development of sophisticated and publicly available software packages (e.g., Andrews et al 2017;Rybizki et al 2017;Philcox & Rybizki 2019;Johnson et al 2021), making this method accessible to many studies aimed at interpreting the chemical evolution of the Milky Way.…”

Section: Introductionmentioning

confidence: 99%

Neutron-capture elements record the ordered chemical evolution of the disc over time

Horta,

Ness,

Rybizki

et al. 2021

Preprint

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The joint abundance-kinematic-age measurements of stars provide the means to link the chemical to the environmental and structural evolution of the Galaxy. An ensemble of nucleosynthetic channels can be leveraged to build a comprehensive chemical account. Using GALAH DR3, we study the element abundances of [Fe/H], [𝛼/Fe], [Ba/Fe], and [Eu/Fe] of ∼50,000 red giant stars, as tracers of the enrichment by supernovae Ia, supernovae II, asymptotic giant branch stars, neutron-star mergers and/or collapsars. We characterise the abundance-age profiles for [Ba/Fe] and [Eu/Fe] in small [𝛼/Fe]-[Fe/H] cells, which serve as an effective reference-frame of supernovae contributions. We find that age-abundance relations vary across the [𝛼/Fe]-[Fe/H] plane. Within cells, we find negative age-[Ba/Fe] relations and flat age-[Eu/Fe] relations. Across cells, we see the slope of the age-[Ba/Fe] relations evolve smoothly and the [Eu/Fe] relations vary in amplitude. We subsequently model our empirical findings in a theoretical setting using the flexible Chempy Galactic chemical evolution (GCE) code using [Fe/H], [Mg/Fe], [Ba/Fe], and age, bringing us closer to the one-zone GCE model concept. We find that within a one-zone framework, an ensemble of environmental parameters vary to explain the data. Using present day orbits from Gaia EDR3 measurements we infer that the environmental parameters, that set the chemical abundance distributions, vary systematically across birth location and time in the disc. Under our modelling assumptions, the data are consistent with a small gradient in the high mass end of the initial mass function (IMF) across the disc, where the IMF is more top heavy towards the inner disc and more bottom heavy in the outer disc.

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“…Such differences will, for example, influence at which [Fe/H] we see the typical knee in the [𝛼/Fe] vs. [Fe/H] plane, at which SNIa kick in (e.g. Tinsley 1979;Gilmore & Wyse 1991;McWilliam 1997;Matteucci 2021). The chrono-chemodynamic data of GALAH+ DR3 is so rich that we cannot address all questions here.…”

Section: Prospects For Chemically Tagging the Accreted Halomentioning

confidence: 96%

The GALAH Survey: Chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and $Gaia$ eDR3

Buder,

Lind,

Ness

et al. 2021

Preprint

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Since the advent of Gaia astrometry, it is possible to identify massive accreted systems within the Galaxy through their unique dynamical signatures. One such system, Gaia-Sausage-Enceladus (GSE), appears to be an early "building block" given its virial mass > 10 10 M at infall (𝑧 ∼ 1 − 3). In order to separate the progenitor population from the background stars, we investigate its chemical properties with up to 30 element abundances from the GALAH+ Survey Data Release 3 (DR3). To inform our choice of elements for purely chemically selecting accreted stars, we analyse 4164 stars with low-𝛼 abundances and halo kinematics. These are most different to the Milky Way stars for abundances of Mg, Si, Na, Al, Mn, Fe, Ni, and Cu. Based on the significance of abundance differences and detection rates, we apply Gaussian mixture models to various element abundance combinations. We find the most populated and least contaminated component, which we confirm to represent GSE, contains 1049 stars selected via [Na/Fe] vs. [Mg/Mn] in GALAH+ DR3. We provide tables of our selections and report the chrono-chemodynamical properties (age, chemistry, and dynamics). Through a previously reported clean dynamical selection of GSE stars, including 30 < √︁ 𝐽 𝑅 / kpc km s −1 < 55, we can characterise an unprecedented 24 abundances of this structure with GALAH+ DR3. Our chemical selection allows us to prevent circular reasoning and characterise the dynamical properties of the GSE, for example mean √︁ 𝐽 𝑅 / kpc km s −1 = 26 +9 −14 . We find only (29 ± 1)% of the GSE stars within the clean dynamical selection region. We thus discuss chemodynamic selections (such as eccentricity and upper limits on [Na/Fe]).

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Modelling the chemical evolution of the Milky Way

Cited by 3 publications

References 264 publications

The homogeneity of the star forming environment of the Milky Way disk over time

The homogeneity of the star forming environment of the Milky Way disk over time

Neutron-capture elements record the ordered chemical evolution of the disc over time

The GALAH Survey: Chemical tagging and chrono-chemodynamics of accreted halo stars with GALAH+ DR3 and $Gaia$ eDR3

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