Milky Way chemo‐dynamics in the era of Gaia

Minchev, Ivan; Chiappini, Cristina; Martig, Marie

doi:10.1002/asna.201612404

Cited by 15 publications

(8 citation statements)

References 36 publications

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“…Further constraints come from large spectroscopic surveys, which have also shown present-day chemical abundance gradients to flatten with increasing height from the Galaxy's midplane (e.g., Chen 2012;Boeche et al 2013Boeche et al , 2014Anders et al 2014;Hayden et al 2014;Minchev 2015). Again, these rather new constraints are readily explained by the MCM13 and MCM14 chemodynamical model (see also Minchev et al 2016 for more details and comparison with other observational constraints). In this respect, the variation of SF histories as a function of cosmic time and galactocentric distance is essential to reproduce chemical abundance diagnostic diagrams as, for instance, the classical [α/Fe] vs. [Fe/H] plot (see Anders et al 2014, 2017a, andreferences therein).…”

Section: Introductionmentioning

confidence: 88%

Gas accretion in Milky Way-like galaxies: temporal and radial dependencies

Nuza

Scannapieco

Chiappini

et al. 2018

Monthly Notices of the Royal Astronomical Society

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One of the fundamental assumptions of chemical evolution models (CEMs) of the Milky Way (MW) and other spirals is that higher gas accretion rates are expected in the past, and in the inner regions of the Galaxy. This leads to the so-called "inside-out disc formation scenario". Yet, these are probably the most unconstrained inputs of such models. In the present paper, we aim at investigating these main assumptions by studying how gas is accreted in four simulated MW-like galaxies assembled within the ΛCDM scenario. The galaxies were obtained using two different simulation techniques, cosmological setups and initial conditions. Two of them are MW candidates corresponding to the chemodynamical model of Minchev et al. (2013Minchev et al. ( , 2014 (known as MCM) and the Local Group cosmological simulation of Nuza et al. (2014). We investigate vertical and radial gas accretion on to galaxy discs as a function of cosmic time and disc radius. We find that accretion in the MW-like galaxies seem to happen in two distinct phases, namely: an early, more violent period; followed by a subsequent, slowly declining phase. Our simulations seem to give support to the assumption that the amount of gas incorporated into the MW disc exponentially decreases with time, leading to current net accretion rates of 0.6 − 1 M yr −1 . In particular, accretion timescales on to the simulated thin-disc-like structures are within ∼ 5 − 7 Gyr, consistent with expectations from CEMs. Moreover, our simulated MW discs are assembled from the inside-out with gas in the inner disc regions accreted in shorter timescales than in external ones, in qualitative agreement with CEMs of the Galaxy. However, this type of growth is not general to all galaxies and it is intimately linked to their particular merger and gas accretion history.

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Section: Introductionmentioning

confidence: 88%

Gas accretion in Milky Way-like galaxies: temporal and radial dependencies

Nuza

Scannapieco

Chiappini

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…To be consistent with the CEM chemical enrichment, which is the direct result of the SFH, the simulation SFH was weighted to match that of the CEM. Further details about the MCM model, comparison to observations, and prediction for future surveys can be found in MCM13, MCM14, Minchev et al (2014bMinchev et al ( , 2016, and Anders et al (2016aAnders et al ( , 2016b …”

Section: The Model Datamentioning

confidence: 99%

“…Further details about the MCM model, comparison to observations and prediction for future surveys can be found in MCM13, MCM14, Minchev et al (2014bMinchev et al ( , 2016; Anders et al (2016a,b).…”

Section: The Model Datamentioning

confidence: 99%

The Relationship Between Mono-Abundance and Mono-Age Stellar Populations in the Milky Way Disk

Minchev

Steinmetz

Chiappini

et al. 2016

ApJ

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Studying the Milky Way disk structure using stars in narrow bins of [Fe/H] and [α/Fe] has recently been proposed as a powerful method to understand the Galactic thick and thin disk formation. It has been assumed so far that these mono-abundance populations (MAPs) are also coeval, or mono-age, populations. Here we study this relationship for a Milky Way chemodynamical model and show that equivalence between MAPs and mono-age populations exists only for the high-[α/Fe] tail, where the chemical evolution curves of different Galactic radii are far apart. At lower [α/Fe]-values an MAP is composed of stars with a range in ages, even for small observational uncertainties and a small MAP bin size. Due to the disk inside-out formation, for these MAPs younger stars are typically located at larger radii, which results in negative radial age gradients that can be as large as 2 Gyr kpc −1 . Positive radial age gradients can result for MAPs at the lowest [α/Fe] and highest [Fe/H] end. Such variations with age prevent the simple interpretation of observations for which accurate ages are not available. Studying the variation with radius of the stellar surface density and scale height in our model, we find good agreement to recent analyses of the APOGEE red-clump (RC) sample when 1-4 Gyr old stars dominate (as expected for the RC). Our results suggest that the APOGEE data are consistent with a Milky Way model for which mono-age populations flare for all ages. We propose observational tests for the validity of our predictions and argue that using accurate age measurements, such as from asteroseismology, is crucial for putting constraints on Galactic formation and evolution.

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“…2 of Minchev et al (2014). Followed by this work, Minchev et al (2015Minchev et al ( , 2016Minchev et al ( , 2018 suggested that migration suppresses flaring in the presence of external perturbations in CDM cosmology. This is in agreement with lots of other cosmological simulations, e.g., Grand et al (2016); Ma et al (2017).…”

Section: Introductionmentioning

confidence: 64%

The Flare and Warp of the Young Stellar Disk traced with LAMOST DR5 OB-type stars

Yu,

Wang,

Cui

et al. 2021

Preprint

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We present analysis of the spatial density structure for the outer disk from 8−14 kpc with the LAMOST DR5 13534 OB-type stars. We discover the clear and similar flaring signatures beyond 8 kpc for which the scale height is from 0.14 to 0.5 kpc in the north and south side, implying that the flaring is possibly symmetrical in the Milky Way disk. We reveal that the thickness of the OB stellar disk is similar with our previous thin disk traced by red giant branch stars, possibly implying that secular evolution is not the main contributor to the flaring but other scenarios such as interactions with passing dwarf galaxies should be more possible. When comparing the OB stellar disk with the gas disk, the former one is moderately thicker than the later one, meaning that one could tentatively use young OB-type stars to trace the gas properties. Meanwhile, we unravel that the scale length of the young OB stellar disk is 1.17 ± 0.05 kpc, which is shorter than gas disk, comfirming that the gas disk is more extended than stellar disk. What is more, by considering the mid-plane displacements (Z 0 ) in our density model we find that almost all are within 100 pc with the increasing trend as Galactocentric distance increases, which looks like the warp signal in young stellar population but the scenarios will need to be investigated in more detail.

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Milky Way chemo‐dynamics in the era of Gaia

Cited by 15 publications

References 36 publications

Gas accretion in Milky Way-like galaxies: temporal and radial dependencies

Gas accretion in Milky Way-like galaxies: temporal and radial dependencies

The Relationship Between Mono-Abundance and Mono-Age Stellar Populations in the Milky Way Disk

The Flare and Warp of the Young Stellar Disk traced with LAMOST DR5 OB-type stars

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