Idealized models for galactic disc formation and evolution in ‘realistic’ ΛCDM haloes

By M. Aumer, Simon D. M. White. 2012

64 citations recorded by the source corpus.

We study the dynamics of galactic disk formation and evolution in 'realistic' LambdaCDM haloes with idealized baryonic initial conditions. We add rotating spheres of hot gas at z=1.3 to two fully cosmological dark-matter-only halo (re)simulations. The gas cools according to an artificial and adjustable cooling function to form a rotationally supported galaxy. The simulations evolve in the full cosmological context until z=0. We vary the angular momentum and density profiles of the initial gas sphere, the cooling time and the orientation of the angular momentum vector to study the effects on the evolution of the disk. The final disks show realistic structural and kinematic properties. The slower the cooling/accretion processes, the higher the kinematic disk-to-bulge ratio D/B of the resulting system. We find that the initial orientation of the gas angular momentum with respect to the halo has a major effect on the resulting D/B. The most stable systems result from orientations parallel to the halo minor axis, but the sign of the spin can have a strong effect. Despite the spherical and coherently rotating initial gas distribution, the orientation of the central disk and of the outer gas components and the relative angle between the components can all change by more than 90 degrees over several billion years. Disks can form from initial conditions oriented parallel to the major axis, but there is often strong misalignment between inner and outer material. The more the orientation of the baryonic angular momentum changes during the evolution, the lower the final D/B. The behaviour varies strongly from halo to halo. Even our simple initial conditions can lead to strong bars, dominant bulges, massive, misaligned rings and counter-rotating components. We discuss how our results may relate to the failure or success of fully cosmological disk formation simulations. (abridged)

Subfields: Astronomy and Astrophysics, Instrumentation

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

Yule-Simpson’s paradox in Galactic Archaeology (2019, background): “…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 2013).”
Constraining the Milky Way assembly history with Galactic Archaeology (2016, background): “Other sources of disc flaring include misaligned gas infall (Scannapieco et al., 2009) and reorientation of the disc rotation axis (Aumer & White, 2013).”
Reconstructing the star formation history of the Milky Way disc(s) from chemical abundances (2014, result): “This functional form is more similar to the SFRs recovered by some ΛCDM cosmological simulations (e.g. Brook et al. 2014; Stinson et al. 2013; Aumer & White 2013).”
A-type stars in the Canada–France Imaging Survey – II. Tracing the height of the disc at large distances with Blue Stragglers (2018, background): “…the midplane of the disc, consistent with early studies of disc-satellite impacts (e.g. Ibata & Razoumov 1998; Velazquez & White 1999; Kazantzidis et al. 2008; Villalobos & Helmi 2008; Purcell et al. 2010) and expectations from cosmological simulations (e.g. Aumer & White 2013; Gómez et al. 2016).”
Dissecting simulated disc galaxies - I. The structure of mono-age populations (2014, background): “Another effect of migration is that, while the profile for young stars often shows a break in the outer regions, as stars move outwards, this break is either erased or moved to larger radii (see also Minchev et al. 2012a; Aumer & White 2013).”
Towards a more realistic population of bright spiral galaxies in cosmological simulations (2013, background): “Moreover, the reorientation of disks (Aumer & White 2013; Okamoto 2013) and disk instabilities (e.g. Noguchi 1999; Aumer et al. 2010) can enhance the bulge-to-disk ratio.”