On the flaring of thick discs of galaxies: insights from simulations
TLDR
In this article, the authors analyse how the flaring of mono-age populations (MAPs) influences the surface density and the age structure of geometrically defined thick discs.Abstract:
Using simulated galaxies in their cosmological context, we analyse how the flaring of mono-age populations (MAPs) influences the flaring and the age structure of geometrically-defined thick discs. We also explore under which circumstances the geometric thin and thick discs are meaningfully distinct components, or are part of a single continuous structure as in the Milky Way. We find that flat thick discs are created when MAPs barely flare or have low surface density at the radius where they start flaring. When looking at the vertical distribution of MAPs, these galaxies show a continuous thin/thick structure. They also have radial age gradients and tend to have quiescent merger histories. Those characteristics are consistent with what is observed in the Milky Way. Flared thick discs, on the other hand, are created when the MAPs that flare have a high surface density at the radius where they start flaring. The thick discs' scale-heights can either be dominated by multiple MAPs or just a few, depending on the mass and scale-height distribution of the MAPs. In a large fraction of these galaxies, thin and thick discs are clearly distinct structures. Finally, flared thick discs have diverse radial age gradients and merger histories, with galaxies that are more massive or that have undergone massive mergers showing flatter age radial gradients in their thick disc.read more
Citations
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The Milky Way's external disc constrained by 2MASS star counts
TL;DR: In this article, the authors used the Two Micron All Sky Survey (hereafter 2MASS) along with the Stellar Population Synthesis Model of the Galaxy, developed in Besancon, to constrain the external disc parameters such as its scale length, its cutoff radius, and the slope of the warp.
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Mapping the Galactic Disk with the LAMOST and Gaia Red Clump Sample VII: the Stellar Disk Structure Revealed by the Mono-abundance Populations
Zheng Yu,Ji Li,Bingqiu Chen,Yang Huang,Shuhua jia,Maosheng Xiang,Haibo Yuan,Jianrong Shi,Chun Wang,Xiaowei Liu +9 more
TL;DR: In this paper, a sample of 96,201 primary red clump (RC) stars selected from the LAMOST and Gaia surveys was used to investigate the stellar structure of the Galactic disk.
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NGC 5746: Formation history of a massive disc-dominated galaxy
Marie Martig,F. Pinna,Jesús Falcón-Barroso,Jesús Falcón-Barroso,Dimitri A. Gadotti,Bernd Husemann,Ivan Minchev,Justus Neumann,Tomás Ruiz-Lara,Glenn van de Ven +9 more
TL;DR: The existence of massive galaxies lacking a classical bulge has often been proposed as a challenge to ''Lambda$CDM'' as discussed by the authors, and it has been shown that a fraction of massive disc galaxies might have very quiescent merger histories, and also that mergers do not necessarily build classical bulges.
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The Milky Way tomography with APOGEE: intrinsic density distribution and structure of mono-abundance populations
Jianhui Lian,Gail Zasowski,Ted Mackereth,Julie Imig,Jon A. Holtzman,Rachael L. Beaton,Jonathan C. Bird,Katia Cunha,J. G. Fern'andez-Trincado,Danny Horta,Richard R. Lane,Karen L. Masters,Christian Nitschelm,Alexandre Roman-Lopes +13 more
TL;DR: In this article , the intrinsic density distribution of MAPs in the Milky Way has been derived by considering the survey selection function and a 2D density model that considers both a broken radial density distribution and radial variation of scale height.
Journal ArticleDOI
Dynamical interplay of disc thickness and interstellar gas: Implication for the longevity of spiral density waves
TL;DR: In this paper , the authors investigate the physical impact of the finite thickness of a galactic disc on the disc stability against the non-axisymmetric perturbations and on the longevity of the spiral density waves, with and without the presence of gas.
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