Vertical disc heating in Milky Way-sized galaxies in a cosmological context

By R. Grand, Volker Springel, F. G'omez, F. Marinacci, Rüdiger Pakmor, D. Campbell, Adrian Jenkins. 2015

117 citations recorded by the source corpus.

Vertically extended, high velocity dispersion stellar distributions appear to be a ubiquitous feature of disc galaxies, and both internal and external mechanisms have been proposed to be the major driver of their formation. However, it is unclear to what extent each mechanism can generate such a distribution, which is likely to depend on the assembly history of the galaxy. To this end, we perform 16 high-resolution cosmological-zoom simulations of Milky Way-sized galaxies using the state-of-the-art cosmological magnetohydrodynamical code AREPO, and analyse the evolution of the vertical kinematics of the stellar disc in connection with various heating mechanisms. We find that the bar is the dominant heating mechanism in most cases, whereas spiral arms, radial migration and adiabatic heating from mid-plane density growth are all subdominant. The strongest source, though less prevalent than bars, originates from external perturbations from satellites/subhaloes of masses log10(M/M⊙) ≳ 10. However, in many simulations the orbits of newborn star particles become cooler with time, such that they dominate the shape of the age–velocity dispersion relation and overall vertical disc structure unless a strong external perturbation takes place.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “…finding supports work showing that migration does not contribute to thick disk formation (e.g., Minchev et al. 2012, 2014a; Vera-Ciro et al. 2014; Grand et al. 2016, see also discussion in §1), except in redistributing stars heated by external mechanisms (Quinn et al. 1993; Villalobos & Helmi…”
The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time (2016, methodology): “Grand et al. (2016a) showed that this trend is a combination of dynamical scatter of star particles and upside-down formation of the disc through the cooling and accretion of star-forming gas.”
Constraints on Radial Migration in Spiral Galaxies - II. Angular momentum distribution and preferential migration (2018, background): “Studies of simulated disc galaxies support the notion that the vertical velocity dispersion of a population negatively affects the degree to which it migrates radially (Vera-Ciro et al. 2014, 2016; Grand et al. 2016).”
The structure and dynamical evolution of the stellar disc of a simulated Milky Way-mass galaxy (2016, methodology): “Nonetheless, radial migration can still occur due to resonance effects in the presence of spiral arms and bars (e.g. Lynden-Bell & Kalnajs 1972; Sellwood & Binney 2002), which is likely to be the dominant mechanism of disk heating (e.g. Grand et al. 2016).”
Estimating stellar birth radii and the time evolution of Milky Way’s ISM metallicity gradient (2018, background): “This finding supports work showing that migration does not contribute to thick disk formation (e.g., Minchev et al. 2012b, MCM14, Vera-Ciro et al. 2014; Grand et al. 2016, see also discussion in §1).”
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).”
7Li evolution in the thin and thick discs of the Milky Way (2018, result): “Several groups have now supported these findings in more recent works (Martig, Minchev & Flynn 2014; Grand et al. 2016), establishing this as a generic result of disk dynamics.”
Theoretical Challenges in Galaxy Formation (2016, background): “With cosmological zoom simulations it has been demonstrated that realistic present day spiral galaxies (Grand et al. 2016; Marinacci, Pakmor & Springel 2014) as well as gas rich massive high-redshift disks (Anglés-Alcázar et al. 2014, Genel et al. 2012) can be formed with a momentum driven wind…”
THE RELATIONSHIP BETWEEN MONO-ABUNDANCE AND MONO-AGE STELLAR POPULATIONS IN THE MILKY WAY DISK (2016, result): “A.1 by MCM14.”