Dissecting simulated disc galaxies - I. The structure of mono-age populations

By M. Martig, I. Minchev, Chris Flynn. 2014

45 citations recorded by the source corpus.

We study seven simulated disc galaxies, three with a quiescent merger history, and four with mergers in their last 9 Gyr of evolution. We compare their structure at z = 0 by decomposing them into “mono-age populations” (MAPs) of stars within 500 Myr age bins. All studied galaxies undergo a phase of merging activity at high redshift, so that stars older than 9 Gyr are found in a centrally concentrated component, while younger stars are mostly found in discs. We find that most MAPs have simple exponential radial and vertical density profiles, with a scale-height that typically increases with age. Because a large range of merger histories can create populations with simple structures, this suggests that the simplicity of the structure of mono-abundance populations observed in the Milky Way by Bovy et al. (2012b,c) is not necessarily a direct indicator of a quiescent history for the Milky Way. Similarly, the anti-correlation between scale-length and scale-height does not necessarily imply a merger-free history. However, mergers produce discontinuities between thin and thick disc components, and jumps in the age-velocity relation. The absence of a structural discontinuity between thin and thick disc observed in the Milky Way would seem to be a good indicator that no merger with a mass ratio larger than 1:15–1:10 occurred in the last 9 Gyr. Mergers at higher redshift might nevertheless be necessary to produce the thickest, hottest components of the Milky Way’s disc.

Subfields: Astronomy and Astrophysics, Instrumentation

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Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “…a theoretical point of view appears to be unavoidable, shown to result from merger perturbations (Kazantzidis et al. 2008; Villalobos & Helmi 2008; Martig et al. 2014), misaligned gas infall (Scannapieco et al. 2009; Roškar et al. 2010) and reorientation of the disk rotation axis (Aumer & White…”
Constraining the thick disc formation scenario of the Milky Way (2014, unknown): “In the simulations of Martig et al. (2014) both cases can occur, depending on the individual simulation considered.”
A RADIAL AGE GRADIENT IN THE GEOMETRICALLY THICK DISK OF THE MILKY WAY (2016, background): “However, to first order, the observed age gradient in the geometrically thick disk is qualitatively consistent with what we find in our simulations (Martig et al. 2014; Minchev et al. 2015) and also independently in simulations by Rahimi et al. (2014) and Miranda et al. (2016).”
THE STELLAR POPULATION STRUCTURE OF THE GALACTIC DISK (2015, background): “The smooth continuum of disk thicknesses found by Bovy et al. (2012a,c) disfavors the satellite accretion and few-satellites-heating scenarios, because those would create a discrete thick-disk component (e.g., Martig et al. 2014).”
Constraining the Milky Way assembly history with Galactic Archaeology (2016, background): “Several independent groups, using different simulation techniques and setups, have confirmed that migration does not thicken the disc (Aumer et al. 2016; Grand et al. 2016; Martig et al. 2014b; Vera-Ciro et al. 2014).”
The age–metallicity structure of the Milky Way disc using APOGEE (2017, methodology): “Structurally, the mono-age populations of simulated galaxies show good agreement with the Milky Way (e.g. Stinson et al. 2013; Bird et al. 2013; Martig et al. 2014a,b).”
The vertical metallicity gradients of mono-age stellar populations in the Milky Way with the RAVE and Gaia data (2017, background): “What is more, Mackereth et al. (2017) showed that mono-age stellar populations flare even for the highest [α/Fe] (see also Martig et al. 2014).”
Chemodynamical evolution of the Milky Way disk II: Variations with Galactic radius and height above the disk plane (2014, methodology): “In accordance with the above results, small (and mostly negative) contribution of radial migration on the age-velocity relation was found also by Martig et al. (2014b), where a suite of seven simulation similar to the one considered in this work was studied.”