Misaligned angular momentum in hydrodynamic cosmological simulations: warps, outer discs and thick discs

By R. Rovskar, V. Debattista, A. Brooks, Thomas R. Quinn, C. Brook, Fabio Governato, J. J. Dalcanton, James Wadsley. 2010

105 citations recorded by the source corpus.

We present a detailed analysis of a disc galaxy forming in a high-resolution fully cosmological simulation to investigate the nature of the outer regions of discs and their relevance for the disc formation process. Specifically, we focus on the phenomenon of misaligned disc components and find that the outer disc warp is a consequence of the misalignment between the inner disc and the surrounding hot gaseous halo. As the infalling cold gas sinks towards the centre of the galaxy, it is strongly torqued by the hot gas halo. By the time the fresh gas reaches the central disc-forming region, its angular momentum is completely aligned with the spin of the hot gas halo. If the spin of the hot gas halo, in turn, is not aligned with that of the inner disc, a misaligned outer disc forms, comprised of newly accreted material. The inner and outer components are misaligned with each other because they respond differently to infalling substructure and accretion. The warped disc feeds the main gas disc due to viscous angular momentum losses, but small amounts of star formation in the warp itself form a low-metallicity thick disc. We show that observations of resolved stellar populations in warped galaxies in the local Universe could provide evidence for the presence of these processes and therefore indirectly reveal ongoing gas accretion and the existence of hot gas haloes.

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).”
Idealized models for galactic disc formation and evolution in ‘realistic’ ΛCDM haloes (2012, background): “Misaligned cosmological infall has been identified as a cause for a variety of phenomena, such as the destruction of discs (CS09), the formation of polar discs (Brook et al. 2008) and the excitation of warps (Roškar et al. 2010).”
Hierarchical formation of bulgeless galaxies – II. Redistribution of angular momentum via galactic fountains (2011, methodology): “In a previous study of angular momentum transfer in similar galaxy formation simulations, Roškar et al. (2010), showed that outer disc warps result from torquing of the cold gas by a massive (misaligned) hot gas halo.”
Radial migration in disc galaxies — I. Transient spiral structure and dynamics (2011, unknown): “2007; de Jong et al. 2007; Roškar et al. 2008b; Azzollini et al. 2008; Bakos et al. 2008; Roškar et al. 2010; Yoachim et al. 2010, 2012, in press; Barker et al. 2011; Alberts et al. 2011).”
Star formation sustained by gas accretion (2014, background): “2012) and gas from cold streams (Roškar et al. 2010; Moran et al. 2012).”
Red Clump Stars from LAMOST II: the outer disc of the Milky Way (2017, background): “As a consequence, a warp can be induced in their outskirts (Shen & Sellwood 2006; Roškar et al. 2010).”